If you are researching in Pennsylvania, you’ll want to know the difference between the Pennsylvania State Archives and the Pennsylvania Archives.
The Pennsylvania State Archives is the physical building with collected records and materials. In state government hierarchy, it comes under the Pennsylvania Historic and Museum Commission (PHMC). Some of the records have been digitized and are available online. The most known digitized record is the PA Death Certificates, 1906-1968 on Ancestry.com. You’ll also find digitized historical maps which are very useful on the Pennsylvania State Archive website.
The (Published) Pennsylvania Archives is a multi-volume series of books, compiled between 1838-1935. There are ten series with a different number of volumes in each series. Many PA historical and genealogical societies have some or all of the series on their shelves. Digitized images of the books are available on Fold3.com. Many of the oldest records of the commonwealth are in these books. And while these aren’t original records but transcriptions, they are easily searchable and readable. A description of what is in each of the ten series is on the Pennsylvania State Archives website.
If you are researching in PA, you’ll want to check out both what is in the Pennsylvania State Archives and the Pennsylvania Archives!