Somerville is a city in Middlesex County, Massachusetts, just north of Boston. As of the 2000 census, the city had a total population of 77,478, and was the most densely populated municipality in New England, and the most dense in the United States outside the New York - New Jersey metropolitan area. It was established as a town in 1842, when it was separated from the urbanizing Charlestown. Somerville apartments for rent comparison page shows most up to date rent information on Somerville apartments and houses. Rent information is obtained from multiple rental sources but we cannot guarantee their accuracy.