Healthcare Access in 10 California Counties (2026 Data)

Primary care physician supply differs more than threefold across these 10 California counties: Alameda has 13.7 per 10,000 residents and Imperial has 4.1. The four lowest, Imperial, Kern, Tulare and Riverside, are all in inland Southern California or the southern San Joaquin Valley.

The counties cover large metro areas, the Central Valley, inland Southern California, the Mexico border and the rural North Coast. GeoChat AI computed all figures from public data. The sources are ACS 2020–2024 5-year estimates, the NPPES October 2026 provider file and HRSA shortage area data.

Key findings

• Physician supply is lowest in four inland counties. Imperial (4.1), Kern (7.0), Tulare (7.2) and Riverside (7.4) have the fewest primary care physicians per 10,000 residents. Alameda (13.7), San Diego (12.5) and Sacramento (12.0) have the most.
• Nurse practitioners narrow some gaps. Imperial is the only county with more primary care nurse practitioners (7.3 per 10,000) than primary care physicians (4.1). Counting both, Imperial (about 11.4) and Riverside (about 12.0) are the two lowest.
• Riverside has the lowest nurse practitioner rate. Its 4.6 per 10,000 is the lowest of the 10, and Humboldt's 8.3 is the highest.
• Three counties are fully covered by primary care shortage areas. Every land census tract in Tulare, Imperial and Humboldt lies inside a primary care HPSA. In each, the coverage comes from several local designations, not one countywide designation. Alameda's primary care designations are for specific facilities only.
• Countywide mental health shortage areas target population groups. Tulare and Imperial have countywide mental health HPSAs for low-income residents. Humboldt's covers low-income, homeless and migrant farmworker residents. Tulare and Imperial also have countywide geographic mental health HPSAs that HRSA has proposed for withdrawal. Kern is fully covered by several local mental health designations.
• Shortage scores do not track physician rates. Imperial has the fewest physicians but the lowest primary care HPSA score of the nine scored counties (15). Fresno has the highest (19). Kern's 19 rests on a designation proposed for withdrawal. Scores also weigh poverty, travel time and other factors (HRSA).
• Humboldt has the oldest population. 19.8% of residents are 65 or older, against 11.9% in Kern and Tulare.
• Los Angeles and Tulare have the highest uninsured rates. About 8.2% and 8.1% of residents lack health insurance, about twice Alameda's 4.0%. Among adults 65 and older, the uninsured rate is 1.6% or lower in every county.

The data

* Rests on a designation HRSA has proposed for withdrawal. In Sacramento, it is the only geographic or population primary care HPSA. In Kern, it sets the score; the highest fully designated score is 18. In Alameda, it is the only mental health HPSA.

† Unreliable: an estimate of 28 people with a margin of error of ±28.

Download the data (CSV). You may reuse it with a link to this page.

How to read these numbers

• Provider rates count registrations, not full-time clinicians. An NPI stays active after a clinician retires or cuts back hours, so these rates are an upper limit. They run higher than the full-time-equivalent ratios HRSA uses. HRSA's primary care count also includes OB/GYNs and excludes nurse practitioners (eCFR), so the ratios are not directly comparable. See provider-to-population ratio.
• Numerator and denominator come from different years. Rates divide an October 2026 provider count by the 2020–2024 average population.
• "Entire county" does not mean one designation covers everyone. It can be several local designations, or one designation for a population group, such as low-income residents. Both are reasons a county with a mid-range physician rate, such as Humboldt, can still be fully covered.
• Proposed withdrawals are still HPSAs. Designations proposed for withdrawal remain recognized until HRSA's final decisions, expected by July 1, 2027 (HRSA). The table counts them and marks where a result depends on one.
• County figures hide local gaps. "Part of county" means some census tracts are outside every designation. Map tracts or ZIP codes to see where the designated areas are.
• Small counties have wider margins of error. ACS estimates for Imperial and Humboldt rest on smaller samples than those for Los Angeles. See ACS 5-year estimates.

Definitions

• Adults 65+ and share 65+: ACS 2020–2024 5-year estimates, table B01001.
• Uninsured: share of the civilian noninstitutionalized population with no health insurance, ACS table B27010.
• Primary care physicians: individual NPIs whose primary taxonomy is family medicine, general internal medicine or pediatrics.
• Primary care NPs: individual NPIs whose primary taxonomy is a primary care nurse practitioner code.
• Provider placement: providers are placed by practice-location ZIP code and assigned to counties with the HUD-USPS ZIP–County crosswalk business address ratios.
• HPSA coverage: "Entire county" means every land census tract lies inside at least one HPSA of that discipline. "Part of county" means some tracts do not. "Facilities only" means the only designations are for specific facilities, such as health centers. Designated HPSAs and those proposed for withdrawal both count.
• Highest score: the highest score among the county's geographic and population primary care HPSAs, including those proposed for withdrawal. Facility HPSAs are excluded. Primary care scores run from 0 to 25 (HRSA); higher scores mean greater need (see HPSA).
• HPSA data dates: HRSA files downloaded October 28, 2026 and rechecked against HRSA's November 2, 2026 files with the same results.

Full processing steps are on the data sources and methods page.

Using this data in a needs assessment

1. Cite the source and year for each figure. Hospital CHNAs must describe the data used; see the CHNA access-gap mapping guide.
2. Confirm HPSA status before you publish. Designations change; check the HPSA ID, type, score and status in HRSA's HPSA Find.
3. Look below the county level. Where a county shows "Part of county," map ZIP codes or tracts to find where the gaps are. In GeoChat AI you can drill into ZIP codes and compare regions.
4. Ask for another county. If you want a county added to this table, tell us.