In January 1931, a U.S. Geological Survey determined that the center of North America was in Pierce County. A pyramid-shaped monument or cairn marking the site is 21 feet high, 6 feet wide at its base, and set on a heart-shaped foundation. It was built across the highway, northwest of its present location, by W.B. Paterson and E.B. Paterson with assistance from local Boy Scouts and other young men in the community, and the Rugby Lions Club donated cement and other materials used in its construction. Completed in August 1932, the cairn is one of many fieldstone structures built in native stone. The structure was moved to its present location in July 1971 when Hwy 2 was four-laned. Nearby, at the northwest corner of the adjacent building, a Native American writing rock said to have been made by early Native Americans is carved with imprints of a human hand, an owl, bear paws, and more.