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.

The United States as of Apr. 20 reached 989,573 COVID-19-related deaths and 80.7 million COVID-19 cases, according to Johns Hopkins University. Currently, 66% of the population is fully vaccinated, and 45% of vaccinated people 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 Apr. 19, 2022. 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. Modoc County, CA

– New cases per 100k in the past week: 11 (1 new cases, -50% change from previous week)
– Cumulative cases per 100k: 11,266 (996 total cases)
— 51.3% less cases per 100k residents than California
– Cumulative deaths per 100k: 90 (8 total deaths)
— 60.0% less deaths per 100k residents than California
– Population that is fully vaccinated: 41.8% (3,695 fully vaccinated)

#49. Siskiyou County, CA

– New cases per 100k in the past week: 11 (5 new cases, 0% change from previous week)
– Cumulative cases per 100k: 16,548 (7,205 total cases)
— 28.5% less cases per 100k residents than California
– Cumulative deaths per 100k: 184 (80 total deaths)
— 18.2% less deaths per 100k residents than California
– Population that is fully vaccinated: 48.9% (21,283 fully vaccinated)

#48. Humboldt County, CA

– New cases per 100k in the past week: 14 (19 new cases, +27% change from previous week)
– Cumulative cases per 100k: 14,687 (19,909 total cases)
— 36.5% less cases per 100k residents than California
– Cumulative deaths per 100k: 105 (143 total deaths)
— 53.3% less deaths per 100k residents than California
– Population that is fully vaccinated: 66.1% (89,601 fully vaccinated)

#47. Glenn County, CA

– New cases per 100k in the past week: 14 (4 new cases, -33% change from previous week)
– Cumulative cases per 100k: 23,136 (6,569 total cases)
— 0.0% more cases per 100k residents than California
– Cumulative deaths per 100k: 169 (48 total deaths)
— 24.9% less deaths per 100k residents than California
– Population that is fully vaccinated: 55.1% (15,647 fully vaccinated)

#46. Madera County, CA

– New cases per 100k in the past week: 14 (22 new cases, -4% change from previous week)
– Cumulative cases per 100k: 27,614 (43,445 total cases)
— 19.4% more cases per 100k residents than California
– Cumulative deaths per 100k: 225 (354 total deaths)
— 0.0% less deaths per 100k residents than California
– Population that is fully vaccinated: 54.3% (85,407 fully vaccinated)

#45. San Benito County, CA

– New cases per 100k in the past week: 16 (10 new cases, -38% change from previous week)
– Cumulative cases per 100k: 21,410 (13,447 total cases)
— 7.5% less cases per 100k residents than California
– Cumulative deaths per 100k: 156 (98 total deaths)
— 30.7% less deaths per 100k residents than California
– Population that is fully vaccinated: 72.1% (45,288 fully vaccinated)

#44. Placer County, CA

– New cases per 100k in the past week: 17 (67 new cases, -26% change from previous week)
– Cumulative cases per 100k: 17,637 (70,255 total cases)
— 23.8% less cases per 100k residents than California
– Cumulative deaths per 100k: 155 (618 total deaths)
— 31.1% less deaths per 100k residents than California
– Population that is fully vaccinated: 66.9% (266,287 fully vaccinated)

#43. Tuolumne County, CA

– New cases per 100k in the past week: 17 (9 new cases, -36% change from previous week)
– Cumulative cases per 100k: 24,245 (13,208 total cases)
— 4.8% more cases per 100k residents than California
– Cumulative deaths per 100k: 330 (180 total deaths)
— 46.7% more deaths per 100k residents than California
– Population that is fully vaccinated: 52.2% (28,457 fully vaccinated)

#42. Kings County, CA

– New cases per 100k in the past week: 18 (28 new cases, -43% change from previous week)
– Cumulative cases per 100k: 36,074 (55,171 total cases)
— 55.9% more cases per 100k residents than California
– Cumulative deaths per 100k: 291 (445 total deaths)
— 29.3% more deaths per 100k residents than California
– Population that is fully vaccinated: 45.0% (68,776 fully vaccinated)

#41. Butte County, CA

– New cases per 100k in the past week: 20 (43 new cases, -14% change from previous week)
– Cumulative cases per 100k: 18,129 (39,736 total cases)
— 21.6% less cases per 100k residents than California
– Cumulative deaths per 100k: 185 (405 total deaths)
— 17.8% less deaths per 100k residents than California
– Population that is fully vaccinated: 53.2% (116,507 fully vaccinated)

#40. Yuba County, CA

– New cases per 100k in the past week: 22 (17 new cases, +31% change from previous week)
– Cumulative cases per 100k: 21,706 (17,076 total cases)
— 6.2% less cases per 100k residents than California
– Cumulative deaths per 100k: 154 (121 total deaths)
— 31.6% less deaths per 100k residents than California
– Population that is fully vaccinated: 49.0% (38,572 fully vaccinated)

#39. El Dorado County, CA

– New cases per 100k in the past week: 23 (45 new cases, +80% change from previous week)
– Cumulative cases per 100k: 15,564 (30,014 total cases)
— 32.7% less cases per 100k residents than California
– Cumulative deaths per 100k: 108 (209 total deaths)
— 52.0% less deaths per 100k residents than California
– Population that is fully vaccinated: 60.8% (117,188 fully vaccinated)

#38. Riverside County, CA

– New cases per 100k in the past week: 24 (591 new cases, -16% change from previous week)
– Cumulative cases per 100k: 25,096 (620,002 total cases)
— 8.5% more cases per 100k residents than California
– Cumulative deaths per 100k: 261 (6,443 total deaths)
— 16.0% more deaths per 100k residents than California
– Population that is fully vaccinated: 58.6% (1,446,610 fully vaccinated)

#37. Lake County, CA

– New cases per 100k in the past week: 26 (17 new cases, +6% change from previous week)
– Cumulative cases per 100k: 18,024 (11,605 total cases)
— 22.1% less cases per 100k residents than California
– Cumulative deaths per 100k: 208 (134 total deaths)
— 7.6% less deaths per 100k residents than California
– Population that is fully vaccinated: 54.8% (35,307 fully vaccinated)

#36. San Joaquin County, CA

– New cases per 100k in the past week: 28 (217 new cases, +3% change from previous week)
– Cumulative cases per 100k: 23,086 (175,952 total cases)
— 0.2% less cases per 100k residents than California
– Cumulative deaths per 100k: 291 (2,220 total deaths)
— 29.3% more deaths per 100k residents than California
– Population that is fully vaccinated: 61.3% (467,117 fully vaccinated)

#35. Calaveras County, CA

– New cases per 100k in the past week: 37 (17 new cases, +183% change from previous week)
– Cumulative cases per 100k: 16,628 (7,633 total cases)
— 28.1% less cases per 100k residents than California
– Cumulative deaths per 100k: 259 (119 total deaths)
— 15.1% more deaths per 100k residents than California
– Population that is fully vaccinated: 53.2% (24,439 fully vaccinated)

#34. Tehama County, CA

– New cases per 100k in the past week: 38 (25 new cases, +92% change from previous week)
– Cumulative cases per 100k: 22,571 (14,690 total cases)
— 2.4% less cases per 100k residents than California
– Cumulative deaths per 100k: 306 (199 total deaths)
— 36.0% more deaths per 100k residents than California
– Population that is fully vaccinated: 42.9% (27,905 fully vaccinated)

#33. Nevada County, CA

– New cases per 100k in the past week: 41 (41 new cases, +193% change from previous week)
– Cumulative cases per 100k: 17,272 (17,230 total cases)
— 25.3% less cases per 100k residents than California
– Cumulative deaths per 100k: 123 (123 total deaths)
— 45.3% less deaths per 100k residents than California
– Population that is fully vaccinated: 63.0% (62,830 fully vaccinated)

#32. Ventura County, CA

– New cases per 100k in the past week: 41 (346 new cases, +16% change from previous week)
– Cumulative cases per 100k: 21,628 (182,971 total cases)
— 6.5% less cases per 100k residents than California
– Cumulative deaths per 100k: 174 (1,474 total deaths)
— 22.7% less deaths per 100k residents than California
– Population that is fully vaccinated: 71.9% (608,688 fully vaccinated)

#31. Kern County, CA

– New cases per 100k in the past week: 42 (375 new cases, +137% change from previous week)
– Cumulative cases per 100k: 26,462 (238,215 total cases)
— 14.4% more cases per 100k residents than California
– Cumulative deaths per 100k: 251 (2,258 total deaths)
— 11.6% more deaths per 100k residents than California
– Population that is fully vaccinated: 53.5% (481,461 fully vaccinated)

#30. Merced County, CA

– New cases per 100k in the past week: 44 (123 new cases, +50% change from previous week)
– Cumulative cases per 100k: 25,523 (70,873 total cases)
— 10.3% more cases per 100k residents than California
– Cumulative deaths per 100k: 293 (813 total deaths)
— 30.2% more deaths per 100k residents than California
– Population that is fully vaccinated: 51.5% (143,077 fully vaccinated)

#29. San Luis Obispo County, CA

– New cases per 100k in the past week: 45 (126 new cases, +30% change from previous week)
– Cumulative cases per 100k: 19,962 (56,515 total cases)
— 13.7% less cases per 100k residents than California
– Cumulative deaths per 100k: 168 (476 total deaths)
— 25.3% less deaths per 100k residents than California
– Population that is fully vaccinated: 64.0% (181,126 fully vaccinated)

#28. Stanislaus County, CA

– New cases per 100k in the past week: 50 (274 new cases, 0% change from previous week)
– Cumulative cases per 100k: 24,505 (134,939 total cases)
— 5.9% more cases per 100k residents than California
– Cumulative deaths per 100k: 294 (1,619 total deaths)
— 30.7% more deaths per 100k residents than California
– Population that is fully vaccinated: 56.8% (312,939 fully vaccinated)

#27. Orange County, CA

– New cases per 100k in the past week: 52 (1,659 new cases, +77% change from previous week)
– Cumulative cases per 100k: 18,579 (590,003 total cases)
— 19.7% less cases per 100k residents than California
– Cumulative deaths per 100k: 219 (6,945 total deaths)
— 2.7% less deaths per 100k residents than California
– Population that is fully vaccinated: 72.4% (2,300,191 fully vaccinated)

#26. Contra Costa County, CA

– New cases per 100k in the past week: 61 (707 new cases, +43% change from previous week)
– Cumulative cases per 100k: 17,609 (203,124 total cases)
— 23.9% less cases per 100k residents than California
– Cumulative deaths per 100k: 113 (1,298 total deaths)
— 49.8% less deaths per 100k residents than California
– Population that is fully vaccinated: 82.2% (947,929 fully vaccinated)

#25. Santa Barbara County, CA

– New cases per 100k in the past week: 66 (293 new cases, +105% change from previous week)
– Cumulative cases per 100k: 20,356 (90,889 total cases)
— 12.0% less cases per 100k residents than California
– Cumulative deaths per 100k: 153 (684 total deaths)
— 32.0% less deaths per 100k residents than California
– Population that is fully vaccinated: 69.0% (308,145 fully vaccinated)

#24. San Diego County, CA

– New cases per 100k in the past week: 67 (2,248 new cases, +12% change from previous week)
– Cumulative cases per 100k: 24,205 (808,047 total cases)
— 4.6% more cases per 100k residents than California
– Cumulative deaths per 100k: 157 (5,229 total deaths)
— 30.2% less deaths per 100k residents than California
– Population that is fully vaccinated: 79.6% (2,656,970 fully vaccinated)

#23. Sutter County, CA

– New cases per 100k in the past week: 71 (69 new cases, +229% change from previous week)
– Cumulative cases per 100k: 23,465 (22,754 total cases)
— 1.4% more cases per 100k residents than California
– Cumulative deaths per 100k: 231 (224 total deaths)
— 2.7% more deaths per 100k residents than California
– Population that is fully vaccinated: 60.4% (58,535 fully vaccinated)

#22. Santa Clara County, CA

– New cases per 100k in the past week: 74 (1,434 new cases, -1% change from previous week)
– Cumulative cases per 100k: 17,006 (327,856 total cases)
— 26.5% less cases per 100k residents than California
– Cumulative deaths per 100k: 118 (2,268 total deaths)
— 47.6% less deaths per 100k residents than California
– Population that is fully vaccinated: 85.4% (1,646,464 fully vaccinated)

#21. Mariposa County, CA

– New cases per 100k in the past week: 76 (13 new cases, +333% change from previous week)
– Cumulative cases per 100k: 15,166 (2,609 total cases)
— 34.4% less cases per 100k residents than California
– Cumulative deaths per 100k: 174 (30 total deaths)
— 22.7% less deaths per 100k residents than California
– Population that is fully vaccinated: 44.4% (7,644 fully vaccinated)

#20. Mono County, CA

– New cases per 100k in the past week: 76 (11 new cases, 0% change from previous week)
– Cumulative cases per 100k: 21,462 (3,100 total cases)
— 7.2% less cases per 100k residents than California
– Cumulative deaths per 100k: 42 (6 total deaths)
— 81.3% less deaths per 100k residents than California
– Population that is fully vaccinated: 62.3% (8,998 fully vaccinated)

#19. Fresno County, CA

– New cases per 100k in the past week: 77 (766 new cases, +44% change from previous week)
– Cumulative cases per 100k: 25,482 (254,590 total cases)
— 10.1% more cases per 100k residents than California
– Cumulative deaths per 100k: 274 (2,739 total deaths)
— 21.8% more deaths per 100k residents than California
– Population that is fully vaccinated: 61.0% (609,666 fully vaccinated)

#18. Inyo County, CA

– New cases per 100k in the past week: 78 (14 new cases, +75% change from previous week)
– Cumulative cases per 100k: 25,328 (4,569 total cases)
— 9.5% more cases per 100k residents than California
– Cumulative deaths per 100k: 310 (56 total deaths)
— 37.8% more deaths per 100k residents than California
– Population that is fully vaccinated: 62.2% (11,229 fully vaccinated)

#17. Los Angeles County, CA

– New cases per 100k in the past week: 82 (8,282 new cases, +34% change from previous week)
– Cumulative cases per 100k: 28,304 (2,841,464 total cases)
— 22.3% more cases per 100k residents than California
– Cumulative deaths per 100k: 315 (31,598 total deaths)
— 40.0% more deaths per 100k residents than California
– Population that is fully vaccinated: 73.1% (7,335,368 fully vaccinated)

#16. Napa County, CA

– New cases per 100k in the past week: 83 (114 new cases, +70% change from previous week)
– Cumulative cases per 100k: 19,533 (26,906 total cases)
— 15.6% less cases per 100k residents than California
– Cumulative deaths per 100k: 104 (143 total deaths)
— 53.8% less deaths per 100k residents than California
– Population that is fully vaccinated: 78.8% (108,600 fully vaccinated)

#15. Yolo County, CA

– New cases per 100k in the past week: 84 (185 new cases, -23% change from previous week)
– Cumulative cases per 100k: 18,126 (39,967 total cases)
— 21.6% less cases per 100k residents than California
– Cumulative deaths per 100k: 141 (311 total deaths)
— 37.3% less deaths per 100k residents than California
– Population that is fully vaccinated: 70.4% (155,131 fully vaccinated)

#14. San Bernardino County, CA

– New cases per 100k in the past week: 91 (1,973 new cases, +63% change from previous week)
– Cumulative cases per 100k: 27,027 (589,219 total cases)
— 16.8% more cases per 100k residents than California
– Cumulative deaths per 100k: 319 (6,948 total deaths)
— 41.8% more deaths per 100k residents than California
– Population that is fully vaccinated: 56.8% (1,237,447 fully vaccinated)

#13. Marin County, CA

– New cases per 100k in the past week: 94 (243 new cases, +57% change from previous week)
– Cumulative cases per 100k: 13,963 (36,141 total cases)
— 39.6% less cases per 100k residents than California
– Cumulative deaths per 100k: 111 (288 total deaths)
— 50.7% less deaths per 100k residents than California
– Population that is fully vaccinated: 87.2% (225,626 fully vaccinated)

#12. Sacramento County, CA

– New cases per 100k in the past week: 96 (1,489 new cases, +64% change from previous week)
– Cumulative cases per 100k: 19,683 (305,498 total cases)
— 14.9% less cases per 100k residents than California
– Cumulative deaths per 100k: 192 (2,978 total deaths)
— 14.7% less deaths per 100k residents than California
– Population that is fully vaccinated: 67.4% (1,046,501 fully vaccinated)

#11. Monterey County, CA

– New cases per 100k in the past week: 100 (436 new cases, +214% change from previous week)
– Cumulative cases per 100k: 21,496 (93,305 total cases)
— 7.1% less cases per 100k residents than California
– Cumulative deaths per 100k: 167 (727 total deaths)
— 25.8% less deaths per 100k residents than California
– Population that is fully vaccinated: 72.6% (315,226 fully vaccinated)

#10. Alameda County, CA

– New cases per 100k in the past week: 103 (1,724 new cases, +73% change from previous week)
– Cumulative cases per 100k: 16,290 (272,253 total cases)
— 29.6% less cases per 100k residents than California
– Cumulative deaths per 100k: 109 (1,829 total deaths)
— 51.6% less deaths per 100k residents than California
– Population that is fully vaccinated: 81.5% (1,361,695 fully vaccinated)

#9. Mendocino County, CA

– New cases per 100k in the past week: 103 (89 new cases, +207% change from previous week)
– Cumulative cases per 100k: 18,640 (16,170 total cases)
— 19.4% less cases per 100k residents than California
– Cumulative deaths per 100k: 141 (122 total deaths)
— 37.3% less deaths per 100k residents than California
– Population that is fully vaccinated: 68.5% (59,461 fully vaccinated)

#8. Santa Cruz County, CA

– New cases per 100k in the past week: 119 (325 new cases, +28% change from previous week)
– Cumulative cases per 100k: 18,314 (50,036 total cases)
— 20.8% less cases per 100k residents than California
– Cumulative deaths per 100k: 96 (261 total deaths)
— 57.3% less deaths per 100k residents than California
– Population that is fully vaccinated: 75.2% (205,347 fully vaccinated)

#7. San Francisco County, CA

– New cases per 100k in the past week: 122 (1,075 new cases, +21% change from previous week)
– Cumulative cases per 100k: 15,364 (135,444 total cases)
— 33.6% less cases per 100k residents than California
– Cumulative deaths per 100k: 97 (854 total deaths)
— 56.9% less deaths per 100k residents than California
– Population that is fully vaccinated: 83.4% (735,605 fully vaccinated)

#6. Sonoma County, CA

– New cases per 100k in the past week: 123 (610 new cases, +67% change from previous week)
– Cumulative cases per 100k: 17,545 (86,731 total cases)
— 24.2% less cases per 100k residents than California
– Cumulative deaths per 100k: 98 (485 total deaths)
— 56.4% less deaths per 100k residents than California
– Population that is fully vaccinated: 78.3% (387,092 fully vaccinated)

#5. Sierra County, CA

– New cases per 100k in the past week: 133 (4 new cases, 0% change from previous week)
– Cumulative cases per 100k: 10,582 (318 total cases)
— 54.3% less cases per 100k residents than California
– Cumulative deaths per 100k: 133 (4 total deaths)
— 40.9% less deaths per 100k residents than California
– Population that is fully vaccinated: 52.2% (1,570 fully vaccinated)

#4. Tulare County, CA

– New cases per 100k in the past week: 133 (618 new cases, +14% change from previous week)
– Cumulative cases per 100k: 28,814 (134,329 total cases)
— 24.6% more cases per 100k residents than California
– Cumulative deaths per 100k: 306 (1,428 total deaths)
— 36.0% more deaths per 100k residents than California
– Population that is fully vaccinated: 54.3% (253,297 fully vaccinated)

#3. San Mateo County, CA

– New cases per 100k in the past week: 154 (1,180 new cases, +48% change from previous week)
– Cumulative cases per 100k: 16,926 (129,753 total cases)
— 26.8% less cases per 100k residents than California
– Cumulative deaths per 100k: 91 (699 total deaths)
— 59.6% less deaths per 100k residents than California
– Population that is fully vaccinated: 84.3% (645,961 fully vaccinated)

#2. Imperial County, CA

– New cases per 100k in the past week: 162 (294 new cases, +29,300% change from previous week)
– Cumulative cases per 100k: 36,801 (66,689 total cases)
— 59.1% more cases per 100k residents than California
– Cumulative deaths per 100k: 502 (910 total deaths)
— 123.1% more deaths per 100k residents than California
– Population that is fully vaccinated: 94.0% (170,393 fully vaccinated)

#1. Plumas County, CA

– New cases per 100k in the past week: 255 (48 new cases, -43% change from previous week)
– Cumulative cases per 100k: 17,520 (3,295 total cases)
— 24.3% less cases per 100k residents than California
– Cumulative deaths per 100k: 69 (13 total deaths)
— 69.3% less deaths per 100k residents than California
– Population that is fully vaccinated: 54.8% (10,314 fully vaccinated)