Marlin, TX has a population of 5,705 and is the 5,942nd largest city in the United States. The population density is 1,263 per sq mi which is 1203% higher than the Texas average and 1294% higher than the national average. The median age in Marlin is 39 which is approximately 15% higher than the Texas average of 34. In Marlin, 47% of the population over 15 years of age are married, 73% speak English and 26% speak Spanish. 77% of Marlin residents were born in Texas, 12% were born out of state, 0% were born outside of the United States and 10% were foreign born.