7 Pa. Code § 137b.26
If land for which preferential assessment is sought lies in more than one taxing district, the county's determination as to whether the land meets applicable minimum acreage requirements for eligible land shall be made on the basis of the total contiguous acreage-without regard to the boundaries of the taxing districts in which the land is located.
Example 1: A landowner has a 100-acre tract of farmland-94 acres of which lie in Township A and 6 acres of which lie in Township B. The landowner files an application seeking preferential assessment of this land. The fact that the tract lies in two separate townships shall be immaterial to the determination of whether the 100-acre tract meets the requirements for preferential assessment under the act.
Example 2: A landowner has a 100-acre tract of farmland-94 acres of which lie in County A and 6 acres of which lie in County B. The landowner files an application seeking preferential assessment. The fact that the tract lies in two separate counties shall be immaterial to the determination of whether the land described in the application meets the requirements for preferential assessment under the act.
7 Pa. Code § 137b.26