San Diego is a city in Duval and Jim Wells counties, Texas, United States.

According to the United States Census Bureau, San Diego has a total area of 1.9 square miles (4.9 km2), all land.

[4] As of the 2020 United States census, there were 3,748 people, 1,390 households, and 916 families residing in the city.

At the 2000 census there were 4,753 people, 1,548 households, and 1,187 families living in the city.

There were 1,793 housing units at an average density of 1,100.4 per square mile (424.9/km2).