The vaccine deployment in December 2020 signaled a turning point in the COVID-19 pandemic. By the end of May 2021, 40% of the U.S. population was fully vaccinated. But as vaccination rates lagged over the summer, new surges of COVID-19 came, including Delta in the summer of 2021, and now the Omicron variant, which comprises the majority of cases in the U.S.

Researchers around the world have reported that Omicron is more transmissible than Delta, making breakthrough and repeat infections more likely. Early research suggests this strain may cause less severe illness than Delta and the original virus, however, health officials have warned an Omicron-driven surge could still increase hospitalization and death rates—especially in areas with less vaccinated populations.

The United States as of Jan. 25 reached 870,916 COVID-19-related deaths and 72 million COVID-19 cases, according to Johns Hopkins University. Currently, 63.4% of the population is fully vaccinated, and 40.1% have received booster doses.

Stacker compiled a list of the counties with highest COVID-19 infection rates in California using data from the U.S. Department of Health & Human Services and vaccination data from Covid Act Now. Counties are ranked by the highest infection rate per 100,000 residents within the week leading up to Jan. 24, 2021. Cumulative cases per 100,000 served as a tiebreaker.

Keep reading to see whether your county ranks among the highest COVID-19 infection rates in your state.

#50. Humboldt County, CA

– New cases per 100k in the past week: 412 (558 new cases, -73% change from previous week)
– Cumulative cases per 100k: 11,413 (15,471 total cases)
— 40.4% less cases per 100k residents than California
– Cumulative deaths per 100k: 92 (125 total deaths)
— 53.3% less deaths per 100k residents than California
– Population that is fully vaccinated: 64.1% (86,830 fully vaccinated)
— 6.3% lower vaccination rate than California

#49. Glenn County, CA

– New cases per 100k in the past week: 479 (136 new cases, -65% change from previous week)
– Cumulative cases per 100k: 19,265 (5,470 total cases)
— 0.5% more cases per 100k residents than California
– Cumulative deaths per 100k: 137 (39 total deaths)
— 30.5% less deaths per 100k residents than California
– Population that is fully vaccinated: 52.9% (15,023 fully vaccinated)
— 22.7% lower vaccination rate than California

#48. Monterey County, CA

– New cases per 100k in the past week: 487 (2,116 new cases, -64% change from previous week)
– Cumulative cases per 100k: 16,212 (70,370 total cases)
— 15.4% less cases per 100k residents than California
– Cumulative deaths per 100k: 150 (651 total deaths)
— 23.9% less deaths per 100k residents than California
– Population that is fully vaccinated: 69.1% (299,763 fully vaccinated)
— 1.0% higher vaccination rate than California

#47. Tehama County, CA

– New cases per 100k in the past week: 496 (323 new cases, -59% change from previous week)
– Cumulative cases per 100k: 18,788 (12,228 total cases)
— 1.9% less cases per 100k residents than California
– Cumulative deaths per 100k: 218 (142 total deaths)
— 10.7% more deaths per 100k residents than California
– Population that is fully vaccinated: 41.2% (26,794 fully vaccinated)
— 39.8% lower vaccination rate than California

#46. Butte County, CA

– New cases per 100k in the past week: 515 (1,129 new cases, -57% change from previous week)
– Cumulative cases per 100k: 14,820 (32,484 total cases)
— 22.7% less cases per 100k residents than California
– Cumulative deaths per 100k: 160 (350 total deaths)
— 18.8% less deaths per 100k residents than California
– Population that is fully vaccinated: 51.3% (112,469 fully vaccinated)
— 25.0% lower vaccination rate than California

#45. El Dorado County, CA

– New cases per 100k in the past week: 518 (998 new cases, -54% change from previous week)
– Cumulative cases per 100k: 12,884 (24,845 total cases)
— 32.8% less cases per 100k residents than California
– Cumulative deaths per 100k: 93 (179 total deaths)
— 52.8% less deaths per 100k residents than California
– Population that is fully vaccinated: 59.3% (114,280 fully vaccinated)
— 13.3% lower vaccination rate than California

#44. Plumas County, CA

– New cases per 100k in the past week: 537 (101 new cases, -42% change from previous week)
– Cumulative cases per 100k: 13,022 (2,449 total cases)
— 32.0% less cases per 100k residents than California
– Cumulative deaths per 100k: 64 (12 total deaths)
— 67.5% less deaths per 100k residents than California
– Population that is fully vaccinated: 53.8% (10,111 fully vaccinated)
— 21.3% lower vaccination rate than California

#43. Mendocino County, CA

– New cases per 100k in the past week: 537 (466 new cases, -67% change from previous week)
– Cumulative cases per 100k: 13,767 (11,943 total cases)
— 28.1% less cases per 100k residents than California
– Cumulative deaths per 100k: 119 (103 total deaths)
— 39.6% less deaths per 100k residents than California
– Population that is fully vaccinated: 66.3% (57,512 fully vaccinated)
— 3.1% lower vaccination rate than California

#42. Shasta County, CA

– New cases per 100k in the past week: 539 (970 new cases, -34% change from previous week)
– Cumulative cases per 100k: 16,987 (30,590 total cases)
— 11.3% less cases per 100k residents than California
– Cumulative deaths per 100k: 250 (450 total deaths)
— 26.9% more deaths per 100k residents than California
– Population that is fully vaccinated: 45.1% (81,143 fully vaccinated)
— 34.1% lower vaccination rate than California

#41. Amador County, CA

– New cases per 100k in the past week: 576 (229 new cases, -52% change from previous week)
– Cumulative cases per 100k: 17,770 (7,064 total cases)
— 7.3% less cases per 100k residents than California
– Cumulative deaths per 100k: 184 (73 total deaths)
— 6.6% less deaths per 100k residents than California
– Population that is fully vaccinated: 51.0% (20,264 fully vaccinated)
— 25.4% lower vaccination rate than California

#40. San Benito County, CA

– New cases per 100k in the past week: 589 (370 new cases, -66% change from previous week)
– Cumulative cases per 100k: 17,757 (11,153 total cases)
— 7.3% less cases per 100k residents than California
– Cumulative deaths per 100k: 140 (88 total deaths)
— 28.9% less deaths per 100k residents than California
– Population that is fully vaccinated: 68.3% (42,884 fully vaccinated)
— 0.1% lower vaccination rate than California

#39. Inyo County, CA

– New cases per 100k in the past week: 615 (111 new cases, -79% change from previous week)
– Cumulative cases per 100k: 21,509 (3,880 total cases)
— 12.3% more cases per 100k residents than California
– Cumulative deaths per 100k: 277 (50 total deaths)
— 40.6% more deaths per 100k residents than California
– Population that is fully vaccinated: 59.8% (10,791 fully vaccinated)
— 12.6% lower vaccination rate than California

#38. Marin County, CA

– New cases per 100k in the past week: 629 (1,627 new cases, -48% change from previous week)
– Cumulative cases per 100k: 11,779 (30,486 total cases)
— 38.5% less cases per 100k residents than California
– Cumulative deaths per 100k: 98 (253 total deaths)
— 50.3% less deaths per 100k residents than California
– Population that is fully vaccinated: 85.6% (221,487 fully vaccinated)
— 25.1% higher vaccination rate than California

#37. Placer County, CA

– New cases per 100k in the past week: 637 (2,539 new cases, -55% change from previous week)
– Cumulative cases per 100k: 14,655 (58,374 total cases)
— 23.5% less cases per 100k residents than California
– Cumulative deaths per 100k: 129 (512 total deaths)
— 34.5% less deaths per 100k residents than California
– Population that is fully vaccinated: 64.5% (256,921 fully vaccinated)
— 5.7% lower vaccination rate than California

#36. Napa County, CA

– New cases per 100k in the past week: 644 (887 new cases, -71% change from previous week)
– Cumulative cases per 100k: 15,103 (20,803 total cases)
— 21.2% less cases per 100k residents than California
– Cumulative deaths per 100k: 81 (111 total deaths)
— 58.9% less deaths per 100k residents than California
– Population that is fully vaccinated: 75.7% (104,298 fully vaccinated)
— 10.7% higher vaccination rate than California

#35. Sutter County, CA

– New cases per 100k in the past week: 650 (630 new cases, -59% change from previous week)
– Cumulative cases per 100k: 19,049 (18,472 total cases)
— 0.6% less cases per 100k residents than California
– Cumulative deaths per 100k: 205 (199 total deaths)
— 4.1% more deaths per 100k residents than California
– Population that is fully vaccinated: 57.4% (55,682 fully vaccinated)
— 16.1% lower vaccination rate than California

#34. Calaveras County, CA

– New cases per 100k in the past week: 656 (301 new cases, -52% change from previous week)
– Cumulative cases per 100k: 13,084 (6,006 total cases)
— 31.7% less cases per 100k residents than California
– Cumulative deaths per 100k: 207 (95 total deaths)
— 5.1% more deaths per 100k residents than California
– Population that is fully vaccinated: 51.7% (23,734 fully vaccinated)
— 24.4% lower vaccination rate than California

#33. Nevada County, CA

– New cases per 100k in the past week: 660 (658 new cases, -52% change from previous week)
– Cumulative cases per 100k: 13,719 (13,685 total cases)
— 28.4% less cases per 100k residents than California
– Cumulative deaths per 100k: 112 (112 total deaths)
— 43.1% less deaths per 100k residents than California
– Population that is fully vaccinated: 61.5% (61,362 fully vaccinated)
— 10.1% lower vaccination rate than California

#32. Tuolumne County, CA

– New cases per 100k in the past week: 674 (367 new cases, -57% change from previous week)
– Cumulative cases per 100k: 18,317 (9,979 total cases)
— 4.4% less cases per 100k residents than California
– Cumulative deaths per 100k: 167 (91 total deaths)
— 15.2% less deaths per 100k residents than California
– Population that is fully vaccinated: 50.7% (27,596 fully vaccinated)
— 25.9% lower vaccination rate than California

#31. Solano County, CA

– New cases per 100k in the past week: 678 (3,036 new cases, -55% change from previous week)
– Cumulative cases per 100k: 15,040 (67,327 total cases)
— 21.5% less cases per 100k residents than California
– Cumulative deaths per 100k: 87 (391 total deaths)
— 55.8% less deaths per 100k residents than California
– Population that is fully vaccinated: 63.9% (285,943 fully vaccinated)
— 6.6% lower vaccination rate than California

#30. Contra Costa County, CA

– New cases per 100k in the past week: 680 (7,848 new cases, -62% change from previous week)
– Cumulative cases per 100k: 14,114 (162,809 total cases)
— 26.3% less cases per 100k residents than California
– Cumulative deaths per 100k: 95 (1,091 total deaths)
— 51.8% less deaths per 100k residents than California
– Population that is fully vaccinated: 79.7% (919,855 fully vaccinated)
— 16.5% higher vaccination rate than California

#29. Stanislaus County, CA

– New cases per 100k in the past week: 685 (3,770 new cases, -54% change from previous week)
– Cumulative cases per 100k: 20,355 (112,088 total cases)
— 6.2% more cases per 100k residents than California
– Cumulative deaths per 100k: 253 (1,393 total deaths)
— 28.4% more deaths per 100k residents than California
– Population that is fully vaccinated: 54.2% (298,362 fully vaccinated)
— 20.8% lower vaccination rate than California

#28. Yuba County, CA

– New cases per 100k in the past week: 700 (551 new cases, -57% change from previous week)
– Cumulative cases per 100k: 17,860 (14,050 total cases)
— 6.8% less cases per 100k residents than California
– Cumulative deaths per 100k: 131 (103 total deaths)
— 33.5% less deaths per 100k residents than California
– Population that is fully vaccinated: 46.4% (36,508 fully vaccinated)
— 32.2% lower vaccination rate than California

#27. San Francisco County, CA

– New cases per 100k in the past week: 707 (6,230 new cases, -61% change from previous week)
– Cumulative cases per 100k: 12,462 (109,859 total cases)
— 35.0% less cases per 100k residents than California
– Cumulative deaths per 100k: 80 (702 total deaths)
— 59.4% less deaths per 100k residents than California
– Population that is fully vaccinated: 81.8% (720,694 fully vaccinated)
— 19.6% higher vaccination rate than California

#26. San Mateo County, CA

– New cases per 100k in the past week: 719 (5,514 new cases, -62% change from previous week)
– Cumulative cases per 100k: 13,271 (101,729 total cases)
— 30.7% less cases per 100k residents than California
– Cumulative deaths per 100k: 76 (585 total deaths)
— 61.4% less deaths per 100k residents than California
– Population that is fully vaccinated: 81.8% (627,070 fully vaccinated)
— 19.6% higher vaccination rate than California

#25. Yolo County, CA

– New cases per 100k in the past week: 723 (1,595 new cases, -49% change from previous week)
– Cumulative cases per 100k: 14,686 (32,382 total cases)
— 23.4% less cases per 100k residents than California
– Cumulative deaths per 100k: 124 (273 total deaths)
— 37.1% less deaths per 100k residents than California
– Population that is fully vaccinated: 67.4% (148,639 fully vaccinated)
— 1.5% lower vaccination rate than California

#24. San Luis Obispo County, CA

– New cases per 100k in the past week: 728 (2,061 new cases, -53% change from previous week)
– Cumulative cases per 100k: 15,915 (45,057 total cases)
— 16.9% less cases per 100k residents than California
– Cumulative deaths per 100k: 136 (385 total deaths)
— 31.0% less deaths per 100k residents than California
– Population that is fully vaccinated: 62.4% (176,720 fully vaccinated)
— 8.8% lower vaccination rate than California

#23. Sacramento County, CA

– New cases per 100k in the past week: 773 (11,998 new cases, -59% change from previous week)
– Cumulative cases per 100k: 15,964 (247,778 total cases)
— 16.7% less cases per 100k residents than California
– Cumulative deaths per 100k: 162 (2,510 total deaths)
— 17.8% less deaths per 100k residents than California
– Population that is fully vaccinated: 64.4% (999,980 fully vaccinated)
— 5.8% lower vaccination rate than California

#22. Mono County, CA

– New cases per 100k in the past week: 775 (112 new cases, -56% change from previous week)
– Cumulative cases per 100k: 19,565 (2,826 total cases)
— 2.1% more cases per 100k residents than California
– Cumulative deaths per 100k: 28 (4 total deaths)
— 85.8% less deaths per 100k residents than California
– Population that is fully vaccinated: 61.9% (8,939 fully vaccinated)
— 9.5% lower vaccination rate than California

#21. Santa Clara County, CA

– New cases per 100k in the past week: 777 (14,987 new cases, -60% change from previous week)
– Cumulative cases per 100k: 13,382 (257,994 total cases)
— 30.2% less cases per 100k residents than California
– Cumulative deaths per 100k: 103 (1,993 total deaths)
— 47.7% less deaths per 100k residents than California
– Population that is fully vaccinated: 83.2% (1,604,234 fully vaccinated)
— 21.6% higher vaccination rate than California

#20. Santa Barbara County, CA

– New cases per 100k in the past week: 779 (3,477 new cases, -59% change from previous week)
– Cumulative cases per 100k: 16,287 (72,722 total cases)
— 15.0% less cases per 100k residents than California
– Cumulative deaths per 100k: 132 (589 total deaths)
— 33.0% less deaths per 100k residents than California
– Population that is fully vaccinated: 66.6% (297,290 fully vaccinated)
— 2.6% lower vaccination rate than California

#19. Merced County, CA

– New cases per 100k in the past week: 779 (2,163 new cases, -55% change from previous week)
– Cumulative cases per 100k: 20,580 (57,147 total cases)
— 7.4% more cases per 100k residents than California
– Cumulative deaths per 100k: 262 (727 total deaths)
— 33.0% more deaths per 100k residents than California
– Population that is fully vaccinated: 48.5% (134,651 fully vaccinated)
— 29.1% lower vaccination rate than California

#18. Alameda County, CA

– New cases per 100k in the past week: 804 (13,439 new cases, -57% change from previous week)
– Cumulative cases per 100k: 12,860 (214,939 total cases)
— 32.9% less cases per 100k residents than California
– Cumulative deaths per 100k: 94 (1,575 total deaths)
— 52.3% less deaths per 100k residents than California
– Population that is fully vaccinated: 78.8% (1,317,216 fully vaccinated)
— 15.2% higher vaccination rate than California

#17. San Joaquin County, CA

– New cases per 100k in the past week: 813 (6,198 new cases, -59% change from previous week)
– Cumulative cases per 100k: 19,252 (146,726 total cases)
— 0.5% more cases per 100k residents than California
– Cumulative deaths per 100k: 257 (1,960 total deaths)
— 30.5% more deaths per 100k residents than California
– Population that is fully vaccinated: 58.0% (441,769 fully vaccinated)
— 15.2% lower vaccination rate than California

#16. Santa Cruz County, CA

– New cases per 100k in the past week: 836 (2,283 new cases, -55% change from previous week)
– Cumulative cases per 100k: 13,028 (35,593 total cases)
— 32.0% less cases per 100k residents than California
– Cumulative deaths per 100k: 87 (237 total deaths)
— 55.8% less deaths per 100k residents than California
– Population that is fully vaccinated: 72.8% (198,809 fully vaccinated)
— 6.4% higher vaccination rate than California

#15. Madera County, CA

– New cases per 100k in the past week: 842 (1,324 new cases, -47% change from previous week)
– Cumulative cases per 100k: 20,994 (33,030 total cases)
— 9.6% more cases per 100k residents than California
– Cumulative deaths per 100k: 209 (329 total deaths)
— 6.1% more deaths per 100k residents than California
– Population that is fully vaccinated: 51.5% (81,086 fully vaccinated)
— 24.7% lower vaccination rate than California

#14. Sonoma County, CA

– New cases per 100k in the past week: 844 (4,174 new cases, -52% change from previous week)
– Cumulative cases per 100k: 13,663 (67,543 total cases)
— 28.7% less cases per 100k residents than California
– Cumulative deaths per 100k: 85 (422 total deaths)
— 56.9% less deaths per 100k residents than California
– Population that is fully vaccinated: 75.8% (374,847 fully vaccinated)
— 10.8% higher vaccination rate than California

#13. Imperial County, CA

– New cases per 100k in the past week: 944 (1,710 new cases, -57% change from previous week)
– Cumulative cases per 100k: 28,727 (52,057 total cases)
— 49.9% more cases per 100k residents than California
– Cumulative deaths per 100k: 453 (820 total deaths)
— 129.9% more deaths per 100k residents than California
– Population that is fully vaccinated: 83.6% (151,411 fully vaccinated)
— 22.2% higher vaccination rate than California

#12. Ventura County, CA

– New cases per 100k in the past week: 956 (8,089 new cases, -53% change from previous week)
– Cumulative cases per 100k: 18,399 (155,655 total cases)
— 4.0% less cases per 100k residents than California
– Cumulative deaths per 100k: 148 (1,250 total deaths)
— 24.9% less deaths per 100k residents than California
– Population that is fully vaccinated: 69.4% (587,494 fully vaccinated)
— 1.5% higher vaccination rate than California

#11. San Bernardino County, CA

– New cases per 100k in the past week: 959 (20,901 new cases, -56% change from previous week)
– Cumulative cases per 100k: 23,570 (513,848 total cases)
— 23.0% more cases per 100k residents than California
– Cumulative deaths per 100k: 287 (6,267 total deaths)
— 45.7% more deaths per 100k residents than California
– Population that is fully vaccinated: 54.2% (1,182,312 fully vaccinated)
— 20.8% lower vaccination rate than California

#10. Tulare County, CA

– New cases per 100k in the past week: 984 (4,586 new cases, -42% change from previous week)
– Cumulative cases per 100k: 22,976 (107,113 total cases)
— 19.9% more cases per 100k residents than California
– Cumulative deaths per 100k: 260 (1,211 total deaths)
— 32.0% more deaths per 100k residents than California
– Population that is fully vaccinated: 51.2% (238,908 fully vaccinated)
— 25.1% lower vaccination rate than California

#9. Fresno County, CA

– New cases per 100k in the past week: 1,062 (10,613 new cases, -35% change from previous week)
– Cumulative cases per 100k: 20,126 (201,080 total cases)
— 5.0% more cases per 100k residents than California
– Cumulative deaths per 100k: 243 (2,429 total deaths)
— 23.4% more deaths per 100k residents than California
– Population that is fully vaccinated: 58.2% (581,043 fully vaccinated)
— 14.9% lower vaccination rate than California

#8. Mariposa County, CA

– New cases per 100k in the past week: 1,110 (191 new cases, +4% change from previous week)
– Cumulative cases per 100k: 11,748 (2,021 total cases)
— 38.7% less cases per 100k residents than California
– Cumulative deaths per 100k: 35 (6 total deaths)
— 82.2% less deaths per 100k residents than California
– Population that is fully vaccinated: 43.3% (7,451 fully vaccinated)
— 36.7% lower vaccination rate than California

#7. Kings County, CA

– New cases per 100k in the past week: 1,134 (1,735 new cases, -43% change from previous week)
– Cumulative cases per 100k: 28,243 (43,195 total cases)
— 47.4% more cases per 100k residents than California
– Cumulative deaths per 100k: 259 (396 total deaths)
— 31.5% more deaths per 100k residents than California
– Population that is fully vaccinated: 42.6% (65,116 fully vaccinated)
— 37.7% lower vaccination rate than California

#6. Riverside County, CA

– New cases per 100k in the past week: 1,153 (28,489 new cases, -39% change from previous week)
– Cumulative cases per 100k: 21,660 (535,126 total cases)
— 13.0% more cases per 100k residents than California
– Cumulative deaths per 100k: 228 (5,623 total deaths)
— 15.7% more deaths per 100k residents than California
– Population that is fully vaccinated: 56.3% (1,389,738 fully vaccinated)
— 17.7% lower vaccination rate than California

#5. Lassen County, CA

– New cases per 100k in the past week: 1,302 (398 new cases, +115% change from previous week)
– Cumulative cases per 100k: 26,716 (8,168 total cases)
— 39.4% more cases per 100k residents than California
– Cumulative deaths per 100k: 180 (55 total deaths)
— 8.6% less deaths per 100k residents than California
– Population that is fully vaccinated: 28.1% (8,582 fully vaccinated)
— 58.9% lower vaccination rate than California

#4. Orange County, CA

– New cases per 100k in the past week: 1,602 (50,875 new cases, -18% change from previous week)
– Cumulative cases per 100k: 16,056 (509,891 total cases)
— 16.2% less cases per 100k residents than California
– Cumulative deaths per 100k: 187 (5,946 total deaths)
— 5.1% less deaths per 100k residents than California
– Population that is fully vaccinated: 70.2% (2,230,634 fully vaccinated)
— 2.6% higher vaccination rate than California

#3. Kern County, CA

– New cases per 100k in the past week: 1,709 (15,384 new cases, +37% change from previous week)
– Cumulative cases per 100k: 21,459 (193,176 total cases)
— 12.0% more cases per 100k residents than California
– Cumulative deaths per 100k: 216 (1,946 total deaths)
— 9.6% more deaths per 100k residents than California
– Population that is fully vaccinated: 50.8% (457,147 fully vaccinated)
— 25.7% lower vaccination rate than California

#2. San Diego County, CA

– New cases per 100k in the past week: 2,161 (72,148 new cases, -26% change from previous week)
– Cumulative cases per 100k: 19,997 (667,568 total cases)
— 4.4% more cases per 100k residents than California
– Cumulative deaths per 100k: 137 (4,559 total deaths)
— 30.5% less deaths per 100k residents than California
– Population that is fully vaccinated: 78.5% (2,618,962 fully vaccinated)
— 14.8% higher vaccination rate than California

#1. Los Angeles County, CA

– New cases per 100k in the past week: 2,495 (250,469 new cases, -14% change from previous week)
– Cumulative cases per 100k: 23,736 (2,382,863 total cases)
— 23.9% more cases per 100k residents than California
– Cumulative deaths per 100k: 279 (28,038 total deaths)
— 41.6% more deaths per 100k residents than California
– Population that is fully vaccinated: 70.4% (7,066,535 fully vaccinated)
— 2.9% higher vaccination rate than California