Medicare in California by county

Most people with Medicare

Across California, 7,258,393 people had Medicare in July 2026, 51% of them in Medicare Advantage or another Medicare health plan. The counties with the most:

1. Los Angeles County 1,717,885 with Medicare · 57% in Medicare Advantage · 65 Advantage plans with drug coverage
2. San Diego County 626,973 with Medicare · 53% in Medicare Advantage · 41 Advantage plans with drug coverage
3. Orange County 607,586 with Medicare · 56% in Medicare Advantage · 57 Advantage plans with drug coverage
4. Riverside County 456,485 with Medicare · 63% in Medicare Advantage · 43 Advantage plans with drug coverage
5. San Bernardino County 350,944 with Medicare · 67% in Medicare Advantage · 45 Advantage plans with drug coverage
6. Santa Clara County 314,272 with Medicare · 50% in Medicare Advantage · 17 Advantage plans with drug coverage
7. Sacramento County 296,376 with Medicare · 62% in Medicare Advantage · 14 Advantage plans with drug coverage
8. Alameda County 279,137 with Medicare · 53% in Medicare Advantage · 14 Advantage plans with drug coverage
9. Contra Costa County 229,619 with Medicare · 52% in Medicare Advantage · 4 Advantage plans with drug coverage
10. Ventura County 178,333 with Medicare · 41% in Medicare Advantage · 15 Advantage plans with drug coverage

All 58 counties, A to Z

• Alameda County279,137 with Medicare · 53% in Medicare Advantage · 14 Advantage plans with drug coverage
• Alpine County281 with Medicare · 14% in Medicare Advantage · 1 Advantage plans with drug coverage
• Amador County12,566 with Medicare · 32% in Medicare Advantage · 4 Advantage plans with drug coverage
• Butte County48,924 with Medicare · 12% in Medicare Advantage · 1 Advantage plans with drug coverage
• Calaveras County14,516 with Medicare · 19% in Medicare Advantage · 1 Advantage plans with drug coverage
• Colusa County4,325 with Medicare · 8% in Medicare Advantage · no Advantage plans listed
• Contra Costa County229,619 with Medicare · 52% in Medicare Advantage · 4 Advantage plans with drug coverage
• Del Norte County6,736 with Medicare · 6% in Medicare Advantage · 1 Advantage plans with drug coverage
• El Dorado County52,647 with Medicare · 42% in Medicare Advantage · 4 Advantage plans with drug coverage
• Fresno County161,815 with Medicare · 49% in Medicare Advantage · 17 Advantage plans with drug coverage
• Glenn County6,005 with Medicare · 8% in Medicare Advantage · 1 Advantage plans with drug coverage
• Humboldt County31,350 with Medicare · 9% in Medicare Advantage · 1 Advantage plans with drug coverage
• Imperial County37,743 with Medicare · 39% in Medicare Advantage · 4 Advantage plans with drug coverage
• Inyo County4,757 with Medicare · 13% in Medicare Advantage · 1 Advantage plans with drug coverage
• Kern County135,793 with Medicare · 48% in Medicare Advantage · 18 Advantage plans with drug coverage
• Kings County19,807 with Medicare · 38% in Medicare Advantage · 12 Advantage plans with drug coverage
• Lake County17,934 with Medicare · 14% in Medicare Advantage · no Advantage plans listed
• Lassen County5,571 with Medicare · 10% in Medicare Advantage · 1 Advantage plans with drug coverage
• Los Angeles County1,717,885 with Medicare · 57% in Medicare Advantage · 65 Advantage plans with drug coverage
• Madera County27,470 with Medicare · 49% in Medicare Advantage · 16 Advantage plans with drug coverage
• Marin County65,094 with Medicare · 45% in Medicare Advantage · 9 Advantage plans with drug coverage
• Mariposa County5,171 with Medicare · 17% in Medicare Advantage · 4 Advantage plans with drug coverage
• Mendocino County24,264 with Medicare · 13% in Medicare Advantage · 1 Advantage plans with drug coverage
• Merced County43,965 with Medicare · 30% in Medicare Advantage · 7 Advantage plans with drug coverage
• Modoc County2,616 with Medicare · 6% in Medicare Advantage · 1 Advantage plans with drug coverage
• Mono County2,185 with Medicare · 9% in Medicare Advantage · 2 Advantage plans with drug coverage
• Monterey County75,137 with Medicare · 17% in Medicare Advantage · 5 Advantage plans with drug coverage
• Napa County32,303 with Medicare · 46% in Medicare Advantage · 3 Advantage plans with drug coverage
• Nevada County31,453 with Medicare · 21% in Medicare Advantage · 2 Advantage plans with drug coverage
• Orange County607,586 with Medicare · 56% in Medicare Advantage · 57 Advantage plans with drug coverage
• Placer County102,960 with Medicare · 56% in Medicare Advantage · 12 Advantage plans with drug coverage
• Plumas County6,516 with Medicare · 12% in Medicare Advantage · 2 Advantage plans with drug coverage
• Riverside County456,485 with Medicare · 63% in Medicare Advantage · 43 Advantage plans with drug coverage
• Sacramento County296,376 with Medicare · 62% in Medicare Advantage · 14 Advantage plans with drug coverage
• San Benito County11,374 with Medicare · 20% in Medicare Advantage · 1 Advantage plans with drug coverage
• San Bernardino County350,944 with Medicare · 67% in Medicare Advantage · 45 Advantage plans with drug coverage
• San Diego County626,973 with Medicare · 53% in Medicare Advantage · 41 Advantage plans with drug coverage
• San Francisco County159,944 with Medicare · 52% in Medicare Advantage · 22 Advantage plans with drug coverage
• San Joaquin County129,888 with Medicare · 55% in Medicare Advantage · 20 Advantage plans with drug coverage
• San Luis Obispo County74,375 with Medicare · 24% in Medicare Advantage · 7 Advantage plans with drug coverage
• San Mateo County144,046 with Medicare · 51% in Medicare Advantage · 16 Advantage plans with drug coverage
• Santa Barbara County86,696 with Medicare · 20% in Medicare Advantage · 4 Advantage plans with drug coverage
• Santa Clara County314,272 with Medicare · 50% in Medicare Advantage · 17 Advantage plans with drug coverage
• Santa Cruz County60,335 with Medicare · 25% in Medicare Advantage · 4 Advantage plans with drug coverage
• Shasta County49,288 with Medicare · 8% in Medicare Advantage · 1 Advantage plans with drug coverage
• Sierra County913 with Medicare · 13% in Medicare Advantage · 1 Advantage plans with drug coverage
• Siskiyou County14,036 with Medicare · 5% in Medicare Advantage · 1 Advantage plans with drug coverage
• Solano County92,924 with Medicare · 56% in Medicare Advantage · 4 Advantage plans with drug coverage
• Sonoma County122,978 with Medicare · 53% in Medicare Advantage · 6 Advantage plans with drug coverage
• Stanislaus County96,830 with Medicare · 58% in Medicare Advantage · 18 Advantage plans with drug coverage
• Sutter County18,749 with Medicare · 9% in Medicare Advantage · 3 Advantage plans with drug coverage
• Tehama County14,935 with Medicare · 11% in Medicare Advantage · 1 Advantage plans with drug coverage
• Trinity County3,657 with Medicare · 4% in Medicare Advantage · no Advantage plans listed
• Tulare County71,443 with Medicare · 37% in Medicare Advantage · 11 Advantage plans with drug coverage
• Tuolumne County16,595 with Medicare · 13% in Medicare Advantage · 1 Advantage plans with drug coverage
• Ventura County178,333 with Medicare · 41% in Medicare Advantage · 15 Advantage plans with drug coverage
• Yolo County37,434 with Medicare · 51% in Medicare Advantage · 12 Advantage plans with drug coverage
• Yuba County14,433 with Medicare · 21% in Medicare Advantage · 3 Advantage plans with drug coverage

Sources: CMS Medicare Monthly Enrollment, July 2026, and the CMS 2027 plan landscape. Medicare Advantage here includes other Medicare health plans, such as cost plans and PACE. Before you meet any agent, check their California license.

Keep reading

• How to find a good Medicare agent near youWhere to look for a local Medicare agent, how to narrow the list to one or two, and the five-minute checks to do before you share anything.
• Medicare Open Enrollment checklist: what to check before December 7A step-by-step checklist for the October 15 to December 7, 2026 Open Enrollment Period: what to read in your plan's letter, what's changing for 2027, what you can switch, and what happens if you do nothing.
• Moving to another state with Medicare: what changes and what to doOriginal Medicare moves with you; most Medicare Advantage and drug plans don't. What happens to each kind of coverage when you move, your window to switch, and why your agent must be licensed in your new state.