Mattapan () is a neighborhood in Boston, Massachusetts. Historically a section of neighboring Dorchester, Mattapan became a part of Boston when Dorchester was annexed in 1870. 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. Predominantly residential, Mattapan is a mix of public housing, small apartment buildings, single-family houses, and two- and three-family houses (known locally as "Three-Deckers" or "Triple-Deckers"). Blue Hill Avenue and Mattapan Square, where Blue Hill Avenue, River Street, and Cummins Highway meet, are the commercial heart of the neighborhood, home to banks, law offices, restaurants, and retail shops. The new Mattapan Branch of the Boston Public library opened 2009, at a cost of more than $4 million. Mattapan has a large portion of green space within the neighborhood. The Harambee Park, the Boston Nature Center and Wildlife Sanctuary, Clark-Cooper Community Gardens, and historic Forest Hill Cemetery can all be considered green space within the neighborhood of Mattapan. Mattapan's demographics are diverse, with a large population of Haitians, Caribbean immigrants, and African Americans. Mattapan has public services such as a recently renovated community health center, and constable services. Mattapan has a trolley running through it, which is accessible via Ashmont. History Indigenous Mattapan was named and first inhabited by Native Americans. Although humans are known to have inhabited eastern North America for at least 15,000 years, the presence of a continental ice sheet extending south to the level of Long Island and Cape Cod would have limited human habitation in Mattapan until the end of the last Ice Age, about 11,700 years ago. Sea level rise since then and disruption of soil layers from urban development in Boston limit the earliest confirmed settlements in the Mattapan area to the Woodland period beginning 2000 years ago, when the archaeological record attests to hunting, fishing, and shellfish gathering around the Neponset River and quarrying for stone points in the Blue Hills. Mattapan was the name given by Massachusett Native Americans to an area north of the Neponset River, possibly meaning "a sitting down place" related to mattappu or "he sits down." It fell within the area controlled by