The Triangle School was built in late 1857 in the Town of Hortonia. It was first called the Elms School because of surrounding trees; then became known as the Triangle School in 1937 after Highway 45 (now Highway 15) went through .
The school closed in 1948 with the consolidation of school districts in the area. It remained closed to the public until 1977 when the Historical Society purchased it. It was used at its original site until 1990 when it was moved to the historical village. The school still contains many of the original furnishings and school pieces including a sand table, clock, and water cooler.