Ferndale, WA has a population of 12,666 and is the 3,277th largest city in the United States. The population density is 1,815 per sq mi which is 1777% higher than the Washington average and 1903% higher than the national average. The median age in Ferndale is 36 which is approximately 4% lower than the Washington average of 38. In Ferndale, 57% of the population over 15 years of age are married, 82% speak English and 8% speak Spanish. 54% of Ferndale residents were born in Washington, 30% were born out of state, 3% were born outside of the United States and 13% were foreign born.