This is an 1873 map of the southwestern portion of the Town of Brookhaven.  Brookhaven Hamlet is in the lower right corner.
The solid curving line running west-east at the bottom of the map is the proposed path of the South Side Railroad extension from Patchogue to Eastport, later to become the Long Island Rail Road.  The actual tracks were not laid along this path when constructed in 1879-1881, but in a slightly more northerly, nearly straight-line path without the curve south into the center of Bellport Village.  Montauk Hwy. was then built adjacent to the railroad, bypassing the Village.