[2] Northern Westmoreland County was once part of the hunting grounds of the Iroquois Five Nations, first settled by Europeans in the 1760s.

In 1852, Allegheny Township, which covered nearly all of the northeastern corner of Westmoreland County, was divided into smaller districts to accommodate a growing population.

Farming, coal mining, and milling were the mainstays of the local economy in the 19th and early 20th century.

[3] According to the United States Census Bureau, the township has a total area of 15.2 square miles (39.3 km2), all land.

Upper Burrell is the site of Penn State New Kensington, and a large research facility of Alcoa.