Derry is a borough in Westmoreland County in the Commonwealth of Pennsylvania, 45 miles (72 km) east of Pittsburgh. The Borough of Derry, consisting of the town area, should not be confused with Derry Township, which is a separate municipality surrounding the borough. In 1900, the population numbered 2,347, and in 1910, 2,954. The population was 2,991 at the 2000 census.
Derry, originally known as Derry Station, was created in 1852 to serve the Pennsylvania Railroad. It was named after the village on PA Route 982 originally known as Derry and now known as New Derry (even though it is older than the community being discussed here). The original "Derry" in Westmoreland County, Pennsylvania was named after the city Derry in Northern Ireland, because the area’s first non-Indian inhabitants were Scotch-Irish.
Derry was ideally suited for major railroad facilities because of its ready access to water from McGee Run (essential in the era of steam locomotives) and because it sits atop a slight summit along the railroad right-of-way. In Derry's heyday in the late 1800s, it had four hotels, mainly to serve railroad workers, as well as a roundhouse for locomotive maintenance and a massive railroad yard. Derry was incorporated as a borough on October 22, 1881.