San Patricio, TX has a population of 406 and is the 20,809th largest city in the United States. The population density is 106 per sq mi which is 9% higher than the Texas average and 16% higher than the national average. The median age in San Patricio is 53 which is approximately 56% higher than the Texas average of 34. In San Patricio, 74% of the population over 15 years of age are married, 68% speak English and 30% speak Spanish. 80% of San Patricio residents were born in Texas, 16% were born out of state, 1% were born outside of the United States and 3% were foreign born.