The first settlers arrived in 1773-1774, having purchased the land from the descendants of William Penn; other pioneers soon bought land from the state government.

Mount Lebanon was a farming community until the arrival of streetcar lines, the first line to Pittsburgh opening on July 1, 1901 followed by a second in 1924. After the arrival of the streetcar lines, which enabled daily commuting to and from Downtown Pittsburgh, Mount Lebanon became a streetcar suburb, with the first real estate subdivision being laid out in November 1901. Further, the opening of the Liberty Tubes in 1924 allowed easy automobile access to Pittsburgh. Between the 1920 and 1930 censuses, the township's population skyrocketed from 2,258 to 13,403... Wikipedia