The Yellowstone River Compact is an interstate compact that was entered into by Montana, North Dakota, and Wyoming and ratified in 1950 for the purpose of providing for an equitable division and apportionment of the waters of the Yellowstone River and its tributaries, encouraging mutually beneficial development and use of the Yellowstone River Basin's waters, and furthering intergovernment cooperation between the three states. The Compact became effective in 1951 and provided for the creation of the Yellowstone River Compact Commission to administer the provisions of the Compact as between the states of Montana and Wyoming.[1][2]