The borough of East Rochester was incorporated in 1908 from Rochester Township, and named for its neighboring community to the west. Once called "Seldom Seen" because the residential areas were separated from the main road by the railroad, the borough is now very much in the manstream of activity.
The Lacock Cemetery and Lacock's Spring in the township serve as a reminder that Abner Lacock, a state senator and one of the county's early leading citizens, lived here. The industrial strip along the river, presently used by construction, storage, and scrap metal firms, was originally occupied by the Rochester Tumbler Works, a major glass producing plant. Part of the Valvoline Oil Company also extends into the borough.
Route 65, one of the county's busiest highways, has attracted many new businesses and restaurants to the borough in the vicinity of K-Mart Plaza, a shopping center that opened in the 1960's. The Pennsylvania Department of Transportation has located its maintenance garage in East Rochester, and the Pennsylvania State Police Drivers' Training center is nearby. The East Rochester-Monaca bridge, built in 1959 to relieve traffic on the Rochester bridge, was the last remaining toll bridge in Pennsylvania until the tolls were removed in 1973, following acquisition by the state.