Alzada, also Stoneville is an unincorporated community and census-designated place in Carter County in the southeastern corner of the U.S. state of Montana. As of the 2010 census it had a population of 29. It is located at the intersection of U.S. Route 212 with Montana Secondary Highways 323 and 326, near the Wyoming and South Dakota borders. The Little Missouri River flows northwards to the west of the community. Alzada is in the Mountain Time Zone.