7 Pa. Code § 138l.34
(a) General. If a parcel of farmland is bisected by the dividing line between two counties, and the portion of the parcel in one county is within an ASA and the portion of the parcel in the other county is not, the portion of the parcel that is not within an ASA shall be automatically included in the ASA if the following apply:
(1) One of the following applies:
(2) An agricultural conservation easement is purchased by any of the following with respect to the parcel:
(iv) The county, the Commonwealth and a local government unit, jointly.
Example 1: A parcel of farmland straddles the boundary line between County A and County B. The portion of the parcel in County A is in an ASA. There is no mansion house on the parcel. The majority of the parcel’s viable agricultural land is in County A. County A purchases an agricultural conservation easement with respect to the entire parcel. Under these facts, as of the purchase of the agricultural conservation easement the portion of the parcel in County B becomes part of the ASA in which the remainder of the parcel is located.
Example 2: A parcel of farmland straddles the boundary line between County A and County B. There is a mansion house on the parcel, and it is located in County A. County A purchases an agricultural conservation easement with respect to the entire parcel. Under these facts, as of the purchase of the agricultural conservation easement the portion of the parcel in County B becomes part of the ASA in which the remainder of the parcel is located.
Example 3: A parcel of farmland straddles the boundary line between County A and County B. There is a mansion house on the parcel, and it straddles the dividing line between County A and County B. County A is the situs of the mansion house for tax purposes. County A purchases an agricultural conservation easement with respect to the entire parcel. Under these facts, as of the purchase of the agricultural conservation easement the portion of the parcel in County B becomes part of the ASA in which the remainder of the parcel is located.
This section cited in 7 Pa. Code § 138l.15 (relating to ASA located in more than one local government unit); and 7 Pa. Code § 138l.21 (relating to effective date of the creation or modification of an ASA).