Census-Online.com - census transcriptions for Washington Co.
Interment.net - cemeteries of  Washington Co.
Mon Valley Veterans of World War II
Washington County GenWeb Projectcollection of online resources for genealogy researchers
Washington County Message Board read and post messages with other genealogy researchers of this county
Washington County, PA - at the American Local History Network Site useful links to genealogy records
Washington County, PA Genealogy Forum read and post messages about your ancestors for this county
Washington Co. Civil War Rolls
The Tombstone Transcription Project - cemeteries for Washington Co; PA
US GenWeb Archives for Washington County cemeteries, newspapers, wills, military rosters etc recorded online here

Additional Resources

Pennsylvania Newspaper Search enter your ancestor's name to instantly search the world's largest newspaper archive; over 12 million newspaper pages
Pennsylvania Birth Records
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Pennsylvania Death Records