The Pennsylvania Historic and Museum Commission, Harrisburg, PA, 17108-1026: See their web site for current information.
They now have the warrant registers available online!! Copy the address below into your browser and hit "enter".
This is the official repository for all land records for the entire Colony of Pennsylvania (later the Commonwealth of Pennsylvania, too). It is located next door to the State Museum in downtown Harrisburg. I suggest to arrange for paid parking lot parking. On-street meters have a two hour limit.
Most records are available, Tuesday through Friday 9 to 5, and Saturday 9 to 12, on microfilm. If there is a significant requirement to see the original records, they may be made available under controlled conditions.
New search room users must register upon entry. A valid drivers license or other good ID is required.
See Donna Bingham Munger's book first, before you visit, so you have your work somewhat organized.
Many resources are available now online: surveys and such.
All Land warrants, surveys, patent documents.
Warrant registers for all PA counties.
Deeds, census data, county records for most PA counties.
Early road lists.
Some PA counties have had all the Land Records research completed by act of the State Legislature. Contact the PA Archives for a listing of what's available, and how it might be procured.
A huge repository for military service, beginning with the Revolutionary War.
YORK COUNTY, PA MASTER LINK - to many offices of history, archives, deeds, wills, etc.
YORK COUNTY ARCHIVES PAGE
YORK COUNTY RECORDER OF WILLS
In some cases, these records have been donated to the local Historical Society. Check the on-line listing for Pennsylvania local and county Historical Societies for more information.