Deer Park, WA has a population of 3,848 and is the 7,620th largest city in the United States. The population density is 560 per sq mi which is 479% higher than the Washington average and 518% higher than the national average. The median age in Deer Park is 36 which is approximately 5% lower than the Washington average of 38. In Deer Park, 53% of the population over 15 years of age are married, 98% speak English and 1% speak Spanish. 68% of Deer Park residents were born in Washington, 31% were born out of state, 0% were born outside of the United States and 1% were foreign born.