Repeaters associated with the AHRA are listed on the ‘Warren Area‘ and ‘Somerset Area‘ pages. These are not the only repeaters in these areas. Here are additional sources for other repeaters not associated with the AHRA:
Coordinated repeaters are listed on the Western Pennsylvania Repeater Council, Inc website, www.wprcinfo.org.
This page allows you to sort coordinated repeaters by frequency, location, or geographic area.
The ARRL publishes repeater listings in the ARRL repeater directory.
Another source for repeater listings is the RFinder Worldwide Repeater Directory application for Android — you can find it by searching for RFinder. It is published by ITWERKS and costs $9.99 to purchase.