St. Jo, TX has a population of 1,077 and is the 14,687th largest city in the United States. The population density is 1,001 per sq mi which is 932% higher than the Texas average and 1005% higher than the national average. The median age in St. Jo is 32 which is approximately 7% lower than the Texas average of 34. In St. Jo, 68% of the population over 15 years of age are married, 97% speak English and 1% speak Spanish. 85% of St. Jo residents were born in Texas, 13% were born out of state, 0% were born outside of the United States and 2% were foreign born.