Maple Valley, WA has a population of 25,093 and is the 1,722nd largest city in the United States. The population density is 4,196 per sq mi which is 4240% higher than the Washington average and 4531% higher than the national average. The median age in Maple Valley is 36 which is approximately 5% lower than the Washington average of 38. In Maple Valley, 68% of the population over 15 years of age are married, 91% speak English and 3% speak Spanish. 52% of Maple Valley residents were born in Washington, 40% were born out of state, 1% were born outside of the United States and 7% were foreign born.