West Deer Township is a township in Allegheny County, Pennsylvania, Pennsylvania, United States. The population was 12,262 at the 2020 census. In 1788, the Pennsylvania Legislature created Allegheny County from some of Westmoreland and Washington counties and most of the Depreciation Lands north of the Ohio River and west of the Alleghen…West Deer Township is a township in Allegheny County, Pennsylvania, Pennsylvania, United States. The population was 12,262 at the 2020 census. In 1788, the Pennsylvania Legislature created Allegheny County from some of Westmoreland and Washington counties and most of the Depreciation Lands north of the Ohio River and west of the Allegheny River. The county was expanded a year later. Of the county's then seven townships, Pitt Township comprised most of the northern part of the county. It is this township that would be divided in 1796 to form Pine and Deer townships. Deer Township was made up of what is today the eastern parts of Richland and West Deer, Frazer, most of East Deer, part of Hampton, and all of Fawn and Harrison. Deer gets its name from Chief Deer, a sub-chief of Iroquois leader Guyasuta. Half of Deer Township was used to create Indiana Township in 1805. In 1836, upon petition of its citizens, Deer was divided into East Deer and West Deer. In 1860, the western boundary of West Deer was moved eastward, the land being used to form Richland Township. In 1861, part of the southwestern corner of West Deer was used to form Hampton Township. West Deer also annexed land along its southern border from Indiana Township in this exchange. Historically, much of West Deer's economy has been based on farming and coal mining. Many coal towns such as Curtisville, Bairdford, and Russellton were dominant forces in the industry. In recent years, significant suburban growth has occurred in the southwestern and central portions of the township, while other portions have remained rural.