This borough was incorporated March 7, 1876, from the western part of Lower St. Clair, Saw-Mill run being nearly identical with the eastern and northern boundaries. The village proper is a small hamlet on the old Pittsburgh and Washington road, but the adjacents of Mount Washington and the country on the line of the Castle Shannon railroad are comparatively thickly settled. The population was 865 in 1880, and has since increased to some extent. A small Methodist Episcopal church is the only religious body. Fetterman postoffice has existed since June, 1876, excepting the period between February 27th and May, 1878. Mary Beltzhoover is the postmistress.