What county is San Diego, TX in?

Updated November 1, 2026 · Data: U.S. Census Bureau

San Diego, Texas is in 2 counties. Most residents (77.7%) live in the Duval County part; the rest live in Jim Wells County.

Which counties do San Diego residents live in?

County	Share of residents	Chart
Duval County	77.7% (2,949 people)
Jim Wells County	22.3% (846 people)

How is San Diego's land split between counties?

County	Share of land area	Chart
Duval County	77.4%
Jim Wells County	22.6%

Inside San Diego, the county depends on the address: check your address privately. See all Texas cities in more than one county or look up another city.

San Diego at a glance

Population3,795Largest place in Duval County

Land area1.9 sq mi1,996 people per sq mi

Share of Duval County30%of the county's residents live here

County seatYes

Time zoneCentralAmerica/Chicago

What ZIP codes are in San Diego?

1 ZIP codes use the name San Diego or are centered in it. Shares are of each ZIP's land; a ZIP named after a town can reach beyond its city limits.

ZIP	Post office name	County (land share)
78384	San Diego	Duval County 99%, Jim Wells County 1%

About Duval County

County seat: San Diego. FIPS code 48131. Population 9,824. All Duval County facts.

Towns near San Diego

Rancho Alegre: 8.5 mi away, Jim Wells County
Alice: 11 mi away, Jim Wells County
Ben Bolt: 11 mi away, Jim Wells County
Benavides: 16 mi away, Duval County
Freer: 25 mi away, Duval County
Premont: 29 mi away, Jim Wells County

San Diego has about 3,795 people. It is an incorporated city or town.

Sources: ACS 2019-2023 5-year (residents by county, table B01003); Census TIGER/Line 2024 and Gazetteer 2024 (land, location); Census 2020 ZCTA file and GeoNames (ZIP codes). Data as of November 1, 2026. Not affiliated with any government agency.