Built about 1882 by mining entrepreneur Noah Armstrong to house his race horses, and featuring a 20 feet (6.1 m)-wide indoor circular aisle that was used for exercising horses, it is a National Register of Historic Places property notable for its unique architecture and as the birthplace of the Thoroughbred racehorse, Spokane, winner of the 1889 Kentucky Derby.

He bought the original property from his son, and purchased additional surrounding land until he owned 4,000 acres (1,600 ha), which he originally named the Doncaster Farm, in honor of the famed English Thoroughbred race horse Doncaster, whom Armstrong admired.

[3] The foundation was set on stone abutments quarried from rock in a canyon located about five miles (8.0 km) away.

[6] The barn featured a 20-foot (6.1 m) wide, indoor training track with dirt footing, claimed to be “nearly a quarter-mile” in circumference,[a] on the ground floor, where Armstrong's horses were exercised.

A circular structure in the center contained the tack room,[2] two hospital stalls, and a spiral stairway.

[3] Charles Armstrong, Noah's son, said the barn "may truly be called a model of architectural beauty and convenience.

This structure is so novel in its conception, so convenient in its economy, and withal so admirably adapted to the purposes of its creation, that a description of it cannot but be of interest to the readers of this sketch.

"[5] Armstrong believed that Montana's high altitude and the nutrient-rich farmland along the Jefferson River made the location ideal for raising superior racehorses.

[3] In 1997, it was purchased by real estate developer and local rancher named Allan Hamilton, who began to renovate the building.

[2] They formed Swift River investments, a Massachusetts-based business, and began to renovate the structure into a community center.