Marshfield is a community located in the U.S. state of Maine. It is within Washington County. It has a total area of 17.54 square miles at 44°44′17″N 67°29′52″W. The elevation is 210 feet above sea level. As of the 2010 census data, it had a total population of 518. The population density was 30.5/sq mi. Estimated per capita income in 2016 was $27,180. It has Zip code 04654.