Sienna Plantation, TX has a population of 15,649 and is the 2,738th largest city in the United States. The population density is 1,180 per sq mi which is 944% higher than the Texas average and 1203% higher than the national average. The median age in Sienna Plantation is 36 which is approximately 5% higher than the Texas average of 34. In Sienna Plantation, 74% of the population over 15 years of age are married, 81% speak English and 9% speak Spanish. 54% of Sienna Plantation residents were born in Texas, 33% were born out of state, 1% were born outside of the United States and 11% were foreign born.