New Sewickley Township was created in 1801 when the original Sewickley Township, then two years old, was divided, leaving the remaining area in North Sewickley Township. Since then, some thirteen other boroughs and townships have been formed from New Sewickley.
The Township's skyline is easily recognized from nearly every high point in the county because of Big Knob, a dome shaped hill nearly 200 feet higher than any of its neighbors and recognized as the county's highest point. The township is mostly rolling farm country, divided by Brush Creek, a mature, often flooded stream in a broad valley, shared (since 1952) with the Pennsylvania Turnpike.
The most prominent village in the township is Unionville, situated where the Zelienople Road (Route 68) crosses Brush Creek. Wallace City, now only a crossroads near the Economy Borough border, was a booming oil town in the 1890's. From this point along Crow's Run to the river once ran the North Shore Railroad, which served not only Wallace City, but the busy Park brickyard and quarries along Crow's Run.
Post offices and villages in the early days of the township included Brush Creek P.O. at Unionville, Sunflower, Knob, Lovi, and Park Quarries.
The earliest church in the township is the Unionville United Methodist, founded prior to 1842. Oak Grove Lutheran Church was formed in 1873. The House Of Mercy Lutheran Church was founded in Crow's Run in 1878 by Dr. William Passavant. Burry's Church, the United Evangelist Protestant St. Johns Congregation, dates back to 1855. The present building occupies an imposing hilltop position in the eastern part of the township.
Still primarily a farming community, New Sewickley has not succumbed to the suburban sprawl that dominates the landscape of neighboring Economy and Rochester Townships. Big Knob Grange holds one of the few remaining annual agricultural fairs in the county. Much potential remains in New Sewickley for development into homesites, recreational areas, or more intensive agricultural land use. New Sewickley Township is part of the Freedom Area School District.