Rochester, WA has a population of 2,912 and is the 8,957th largest city in the United States. The population density is 1,250 per sq mi which is 968% higher than the Washington average and 1279% higher than the national average. The median age in Rochester is 38 which is approximately 2% higher than the Washington average of 38. In Rochester, 67% of the population over 15 years of age are married, 94% speak English and 5% speak Spanish. 67% of Rochester residents were born in Washington, 28% were born out of state, 2% were born outside of the United States and 3% were foreign born.