16 Pa. Stat. § 9851
In the addition to the indexes which the recorder of deeds in each county of this commonwealth is required to keep, the said recorder shall carefully and accurately prepare and keep in his office two general indexes of all deeds recorded therein, in one of which, to be known as the direct index, he shall enter in their order the name of the grantor, the name of the grantee, the volume and page wherein the deed is recorded, and in the other, to be known as the ad sectum index, he shall enter in their order the name of the grantee, the name of the grantor, the volume and page wherein the deed is recorded. He shall in like manner also prepare and keep two general indexes, one direct and the other ad sectum, of all mortgages recorded in his office. In counties of the second class, he shall hereafter enter in both said indexes of deeds and in both the indexes of mortgages, the date of recording and the name of the city or borough or township and the number of the ward thereof, if any, in which the property affected is stated in the recorded instrument to be located, and the primary as well as the permanent indexes shall contain the foregoing entries as to date of recording and locality of each property affected: Provided, That where an instrument affects property in more than one ward, city, borough, town or township and the space on the index is insufficient to permit the writing of the locality of each property affected, the name of the county alone shall be full compliance with this act. Said indexes shall be arranged alphabetically and in such a way as to afford an easy and ready reference to said deeds and mortgages respectively, and shall be written in a plain and legible hand: Provided however, That in any county where such indexes have already been prepared and in use, or where any special law relating to any of said indexes is now in force, they shall be adopted and kept as if made in pursuance of this act. Nothing herein contained shall prohibit the recorder of deeds from combining the general indexes for deeds with the general indexes for mortgages into one general index.
16 P.S. § 9851