As farmers and ranchers homesteaded the arid, treeless plains of northwestern Rosebud County, Ingomar was platted along the tracks of the Chicago, Milwaukee & St. Paul Railway in 1912, and that year one teacher and a borrowed building served its first public school students. By the following year, the western one-room portion of the present building was completed and fourteen students attended classes. In 1915, the school district hired Melstone builder Neils Hanson to construct an addition, and at a cost of $9,000 the enlarged schoolhouse served local children and provided a place for community functions. The teachers and their thirty-seven scholars presented a dedication program on November 24, 1915, for the visiting State Inspector of Schools. The school remained well attended during the 1920s and 1930s partly because other nearby rural schools closed. A second building, no longer standing, was built in 1922 for elementary students, and the original building was then converted to use as a high school, serving until 1951 and again briefly during the 1960s. Activity at the site ended permanently when Ingomar’s school district closed in 1992. Its spacious, well-lighted classrooms with hardwood floors, wood wainscot walls, and pressed tin ceilings remain intact, and the building survives as one of the area’s few examples of public architecture and as eastern Montana’s most outstanding example of post-frontier prairie schoolhouse design, with its appearance virtually unchanged by time and service.