There is also Allegheny County and several Allegheny Townships in Pennsylvania.

Allegheny was a city in western Pennsylvania, located on the north shore of the junction of the Allegheny and Ohio Rivers, across from Pittsburgh. It has since been absorbed by the neighboring larger city as the neighborhood of Northside. When the two cities were joined, both of the old ward systems were discarded. They were replaced by a new ward system made of 27 wards. In the new ward system, Allegheny, Pennsylvania became wards 21 to 27, thus its past location is easily determinable by viewing a map that depicts the ward system. The absorption of Allegheny, Pennsylvania began in 1906, was effected in 1907, and finally approved by the United States Government in 1911. The population of Pittsburgh, Pennsylvania rose from 321,616 in 1900 to 533,905 in 1910, which included the 132,283 who lived in Allegheny, Pennsylvania in 1910 when the last census of Allegheny, Pennsylvania was taken. Andrew Carnegie constructed early one of his Carnegie Free Public Libraries in Allegheny, Pennsylvania. "Allegheny, Pennsylvania" is an acceptable city/town designation for postal addresses, with a ZIP Code of 15212.

Allegheny, Pennsylvania was laid out in 1788, and the lots were sold in Philadelphia by the State government. It was incorporated as a borough in 1828 and as a city in 1840. The population rose to 53,180 in 1870, which is about the time when two recognizable entities sprang forth. A religious denomination called Jehovah's Witnesses was born, and a food processing company called the H.J. Heinz Company built its factory there close to the Chestnut Street bridge over the Allegheny River, which has been replaced by the 16th Street bridge. Today, both the Jehovah's Witnesses and the H.J. Heinz Company have crossed the ocean and are known to people of other nations.

As of now, two edifices associated with the sports industry exist there. They are known to many Americans. PNC Park is the home field of the professional baseball team named the Pittsburgh Pirates, and Heinz Field is the home field of the professional football team named the Pittsburgh Steelers. Those facilities replaced an edifice called Three Rivers Stadium in which both teams had played their home games. Towards the end of the 19th century and the start of the 20th century, The Pittsburgh Pirates had performed at Exposition Park which was located in "Allegheny City" (Allegheny, Pennsylvania).