Garrison is located about 48 miles east of Helena at the junction of Highway 12 and Interstate 90. Garrison is not far from the 1,500-acre Grant-Kohrs Ranch National Historic Site in Deer Lodge. This was the headquarters for one of the largest and best known 19th-century range ranches in the country. Today the ranch house, bunkhouse and outbuildings are much as they were during ranch operations from the 1860s through the 1960s.