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Washington Medicare, by the Numbers

The data layer behind our Washington guide and all 53 city pages, in one place: CMS enrollment, Census demographics, and federal shortage designations, county by county.

Plans we accept in Washington covering ~65.7% of Washington's Medicare beneficiaries
  • Original Medicare
  • UnitedHealthcare ~26% of MA members
  • Wellcare ~4% of MA members

Coverage data 2024. Plan networks change - we confirm exactly what your plan covers before any work begins.

1,558,115Medicare beneficiaries statewide (2025)
49.2%chose Medicare Advantage plans
232,931dual-eligible for Medicare and Apple Health
318,838Washingtonians 65+ live alone
167 minmedian ER visit statewide (CMS)
219federal primary-care shortage designations

Medicare Enrollment by County

Counties covered by our city pages (22 counties, 1,436,707 beneficiaries). Each links to its anchor city page.

County Medicare beneficiaries Medicare Advantage share Dual-eligible Residents 65+ Shortage designations
King County 361,153 53.6% 57,369 311,368 24
Pierce County 172,986 51.1% 27,152 133,313 8
Snohomish County 149,506 59.4% 21,594 120,158 12
Spokane County 121,092 56.6% 20,960 92,555 8
Clark County 105,925 66.8% 13,712 83,012 2
Thurston County 69,506 52.5% 9,224 54,324 5
Kitsap County 65,719 39.6% 7,002 52,865 6
Whatcom County 53,410 47% 7,212 42,255 4
Yakima County 46,461 46% 10,744 36,622 19
Benton County 41,184 31.1% 5,695 32,722 4
Skagit County 35,607 44.7% 4,132 28,810 4
Clallam County 29,496 23% 3,282 24,426 11
Cowlitz County 28,987 66.7% 4,939 21,762 4
Island County 26,962 41.4% 1,953 22,640 1
Lewis County 23,100 55.5% 3,821 17,779 11
Grays Harbor County 22,567 25.1% 4,154 17,438 12
Chelan County 19,965 39.4% 2,728 16,291 5
Grant County 18,089 35.2% 3,466 14,393 10
Walla Walla County 14,787 32.7% 2,139 12,073 2
Franklin County 12,549 35.3% 2,422 9,857 3
Kittitas County 10,634 27.2% 1,236 7,691 4
Whitman County 7,022 28.4% 985 5,456 1

Statewide, 49.2% of beneficiaries chose Medicare Advantage in 2025. Counties above that line see more prior authorizations and more denials worth appealing; counties below it lean on Medigap timing. Washington is one of the most flexible Medigap states in the country: once you have held a policy for 90 days, you can switch to a plan with equal or lesser benefits at any time of year, from any insurer, with no medical underwriting (RCW 48.66.045), though the state does not require insurers to offer Medigap to under-65 beneficiaries who qualify through disability. About 8.5% of Washington seniors live below the poverty line, the group most likely to qualify for unclaimed help: federal Extra Help and the Medicare Savings Programs, which the Health Care Authority runs with an income test and no asset test (Washington has no income-based state drug program). For the full rundown, sources included, see our Washington patient advocacy hub.

The Numbers Are the Backdrop. The Help Is the Point.

One dedicated advocate for the bills, appeals, appointments, and paperwork, serving every Washington county virtually, usually at $0 with Medicare.

Or start from your city: every Washington city we serve.

Sources: CMS Medicare Monthly Enrollment (2025); US Census Bureau ACS 2023 5-year; CMS Care Compare Timely & Effective Care (median ER minutes, period ending 09/30/2025); HRSA Health Professional Shortage Area designation file. Data retrieved 2026-08-18. Understood Care is an independent private advocacy service, not a government agency.