The Blackfeet Indians called the creek running near this town Un-es-putcha-eka which translated to "Big Sandy Creek" and the town was named for the creek. This is one of the more colorful towns of the Old West. Novelist B.M. Bower lived here and used this town as the model for "Dry Lake" in her Flying U novels. Charles Russell worked on some of the nearby ranches.
John Willard, in his book Adventure Trails in Montana, writes, "Big Sandy was a cow town of long tradition and a freighting center when goods were unloaded at the Coal Banks Landing just south of here on the Missouri River. Materials for Fort Assiniboine were delivered at Coal Banks by river steamer, then freighted overland to the fort."
The railroad found the water source to its liking and erected a water tower nearby along with the McNamara freight depot. History records that a saloon was opened in a tent near McNamara and Marlow’s freight depot in 1886 followed soon after by another saloon, the Log Cabin. These two depots, the saloons (nine in all—mostly tents with wood floors), a warehouse, and a boxcar that the section foreman lived in made up the beginnings of the town. As the town grew, and the number of cowboys, settlers, and railroad men increased, the Spokane Hotel was built to accommodate the increased traffic.
By 1912 the town was booming with homesteaders and the Great Northern Railroad moved its depot into town. Before that, a horse-drawn shuttle bus carted passengers to and from the train a short distance away. The 1-1/2 mile ride cost a mere 50¢. By 1919, the homesteader boom was a bust. Many sold out and moved on. Those that stayed bought what the others sold and became sustainable sized farms.