Mount Vernon, WA has a population of 33,388 and is the 1,273rd largest city in the United States. The population density is 2,712 per sq mi which is 2705% higher than the Washington average and 2893% higher than the national average. The median age in Mount Vernon is 34 which is approximately 10% lower than the Washington average of 38. In Mount Vernon, 56% of the population over 15 years of age are married, 66% speak English and 28% speak Spanish. 48% of Mount Vernon residents were born in Washington, 30% were born out of state, 2% were born outside of the United States and 19% were foreign born.