The J. C. Adams Stone Barn is a historic Romanesque Revival barn constructed of stone and wood located about 1 mile (1.6 km) northeast of the town of Sun River, Montana, in the United States. It is just south of U.S. Route 89. It is the only Romanesque Revival stone barn in the United States located west of the Mississippi River. Chere Jiusto, Christine Brown, and Tom Ferris of the Montana Historical Society have described the Adams Stone Barn as "one of Montana's most-beloved and best-known landmark barns." The structure was added to the National Register of Historic Places on January 12, 1979.