Alder is located in Madison County 9 miles west of Virginia City along Hwy 287 near the junction with US 287. The gateway to the Upper Ruby Valley and the Ruby River Reservoir, it is also near Beaverhead National Forest.
Alder is the former Robbers' Roost of early gold rush days. The post office started in 1863. B.F. Chambers established a sawmill in the early 1880s, and by 1884 the community had water-powered sawmills, two churches, two general stores, cotton gins, a district school, and forty residents.