 Brookline became an exclave in 1873, when the neighboring town of West Roxbury was annexed by Boston (and left Norfolk County to join Suffolk County), and Brookline refused to be annexed by Boston after the Boston–Brookline annexation debate of 1873.Brookline separates the bulk of the city of Boston (except for a narrow neck or corridor near the Charles River) from its westernmost neighborhoods of Allston–Brighton, which had been the separate town of Brighton until annexed by Boston in 1873.There are many neighborhood associations, some of which overlap.