The original agricultural community of Menotomy was established as a section of Cambridge. In 1807 West Cambridge became a separate community, renamed Arlington in 1867. A few early farmhouses survive, especially along Massachusetts Avenue, the route to Revolutionary conflicts in Lexington and Concord. Although there were mills along Mill Brook from the seventeenth century on, the development of a distinct mill district—both industrial and residential—followed the Revolution. The arrival of the railroad in 1846 and of the horse street railroad in 1859 made Arlington Center a popular commuter community. Many fine examples of middle- or upper-middle-income residences from the mid-nineteenth through the early twentieth century abound in the Pleasant Street Historic District (NRD) and the Jason-Gray Historic District (NRD). Individual wealth influenced the establishment of a distinguished group of public and commercial buildings in Arlington Center.