Mattapan is a neighborhood in Boston, Massachusetts, United States. Mattapan is the original Native American name for the Dorchester area, possibly meaning "a place to sit." At the 2010 census, it had a population of 36,480, with the majority of its population immigrants. Like other neighborhoods of the late 19th and early 20th century, Mattapan developed, residentially and commercially, as the railroads and streetcars made downtown Boston increasingly accessible.