Mesa, WA has a population of 371 and is the 21,305th largest city in the United States. The population density is 229 per sq mi which is 137% higher than the Washington average and 153% higher than the national average. The median age in Mesa is 26 which is approximately 31% lower than the Washington average of 38. In Mesa, 57% of the population over 15 years of age are married, 34% speak English and 66% speak Spanish. 36% of Mesa residents were born in Washington, 23% were born out of state, 0% were born outside of the United States and 40% were foreign born.