Markham, TX has a population of 1,039 and is the 14,918th largest city in the United States. The population density is 462 per sq mi which is 377% higher than the Texas average and 410% higher than the national average. The median age in Markham is 34 which is approximately equal to the Texas average of 34. In Markham, 62% of the population over 15 years of age are married, 69% speak English and 31% speak Spanish. 81% of Markham residents were born in Texas, 5% were born out of state, 3% were born outside of the United States and 12% were foreign born.