Martinsdale is located in central Montana between the Castle and Crazy Mountains along the north fork of the Musselshell River. The area's origins are in sheep ranching with two of the largest sheep outfits in the state; the Smith ranch to the west and the Bair spread to the east. Charles M. Bair was one of the most successful sheep ranchers in the world, at one time running over 300,000 head. Today, sheep and cattle ranching coexist with a myriad of recreation opportunities including fishing, boating, hiking, wildlife watching, mountain biking and hunting.
Martinsdale is located in central Montana, 23 miles west of Harlowton on US Highway 12.