16 Pa. Stat. § 9104
When the boundary line between any two or more counties has been ascertained, determined, surveyed, located, relocated, designated or marked, as provided by the act of August 9, 1955 (P.L. 323), known as "The County Code," or any other act authorizing the fixing, relocation or marking of county lines, and land located in one county or lying along or near the boundary line of one county, the deed for which has been duly recorded in said county, is found or has become by said survey or proceeding to be all or partially within the limits of an adjoining county, the deed for the same, if recorded in the said adjoining county any time prior to one year after the report and map resulting from said survey or proceedings has been approved and recorded in the records of the Court of Quarter Sessions in the said adjoining county, shall have the same force, efficacy, validity and effect, as if originally recorded therein at the time the deed was recorded in the first mentioned county, and mortgages, judgments, or other liens recorded in the first mentioned county may also be recorded in the said adjoining county in the same manner as deeds, with like force and effect.
16 P.S. § 9104