U.S. Sup. Ct.;
15–214

The St. Croix River, which forms part of the boundary between Wisconsin and Minnesota, is protected under federal, state, and local law. Petitioners own two adjacent lots—Lot E and Lot F—along the lower portion of the river in the town of Troy, Wisconsin. For the area where petitioners' property is located, state and local regulations prevent the use or sale of adjacent lots under common ownership as separate building sites unless they have at least one acre of land suitable for development. A grandfather clause relaxes this restriction for substandard lots which were in separate ownership from adjacent lands on January 1, 1976, the regulation's effective date.

Petitioners' parents purchased Lots E and F separately in the 1960's, and maintained them under separate ownership until transferring Lot F to petitioners in 1994 and Lot E to petitioners in 1995. Both lots are over one acre in size, but because of their topography they each have less than one acre suitable for development. The unification of the lots under common ownership therefore implicated the rules barring their separate sale or development. Petitioners became interested in selling Lot E as part of an improvement plan for the lots, and sought variances from the St. Croix County Board of Adjustment. The Board denied the request, and the state courts affirmed in relevant part. In particular, the State Court of Appeals found that the local ordinance effectively merged the lots, so petitioners could only sell or build on the single combined lot.