When you're filing for an expungement in Pennsylvania, in almost all instances, the expungement pleading would have to be filed at the Clerk of Courts, in the applicable county where the criminal case took place. The Clerk of Courts at the court of Common Pleas in the applicable county is where the filings would have to be filed.
There are 67 counties in Pennsylvania. In all instances, you have to follow the expungement pleadings, you have to get them time-stamped. If it's a matter of getting the consent of the district attorney's office which you are required to do, in essence, in all counties. A limited number of counties in Pennsylvania require you to get the consent of the district attorney's office before the process goes to a certain point.
Again, that's the exception, not the rule. Fundamentally, when you're filing, it needs to be done in the court of Common Pleas at the clerk of courts in the county where the criminal case took place. Having an experienced Pennsylvania criminal defense attorney will help you best understand and navigate the expungement process and they should be involved from as early as possible in the case.