Texas Porch
Rio Grande Valley / Border

San Diego, Texas

San Diego is the seat of Duval County, in the South Texas brush country west of Corpus Christi and northeast of Laredo. The town sits amid the ranching lands and mesquite country of the region, an area with deep roots in Spanish and Mexican land grants that predate the county itself. It served as an early trade and county center as the surrounding country was settled through the nineteenth century.

Place essentials

Official Census snapshot
Census place type
City
July 2025 population
3,503
Change from 2020 base
-6.4%
Land area
1.9 sq. mi.
County footprint
Duval County and Jim Wells County

Place type, county footprint, and land area use the Census Bureau's January 1, 2025 geography. Population uses Vintage 2025 estimates through July 1, 2025; change compares that estimate with the April 1, 2020 estimates base. Geography file | Population file

San Diego crosses county lines, so the appraisal district and tax office depend on the parcel address. School, city-limit, MUD, PID, and other special-district lines can be different too. Start with the full county list below instead of treating one county as the answer.

Official routes

Use the office for the parcel address; a mailing city is not always the governing city.

County context

What to know around San Diego

County lines carry much of the property, land, water, and outdoors context around San Diego.

Nearby

Places near San Diego

Nearby counties

Local notes for nearby counties

Next steps for San Diego