Petersburg, TX has a population of 1,158 and is the 14,252nd largest city in the United States. The population density is 1,431 per sq mi which is 1167% higher than the Texas average and 1480% higher than the national average. The median age in Petersburg is 36 which is approximately 5% higher than the Texas average of 34. In Petersburg, 67% of the population over 15 years of age are married, 52% speak English and 47% speak Spanish. 81% of Petersburg residents were born in Texas, 10% were born out of state, 0% were born outside of the United States and 8% were foreign born.