20 Pa.C.S. § 3151

Letters testamentary or of administration on the estate of a decedent domiciled in the Commonwealth at the time of his death shall be granted only by the register of the county where the decedent had his last family or principal residence. If the decedent had no such domicile in the Commonwealth, letters testamentary or of administration may be granted by the register of any county wherein property of the estate shall be located and, when granted, shall be exclusive throughout the Commonwealth. If the decedent had no such domicile in the Commonwealth, and had no property located therein, and service of process is to be made in the Commonwealth upon his personal representative as authorized by law, then letters testamentary or of administration on his estate may be granted by the register of any county of the Commonwealth and, when granted, shall be exclusive throughout the Commonwealth.