Mercer Island Population 2024 Map. The exact population of mercer island, washington as of june 2024 is estimated at 24,748 residents. Mercer island, washington is the 1,529th largest city in the us.
25,464), including age, race, sex, income, poverty, marital status, education and more. Current, historical, and projected population, growth rate, median age, population density, urbanization, and urban population.