Water rights often decide what a ranch in Roosevelt County is worth and how much hay and grass it can grow. Before you buy, lease or irrigate ground here, check the Roosevelt County water rights tied to it with the tools below. For current snowpack, drought and cattle movement, see the Roosevelt County, Montana page; statewide rules are at the Montana DNRC water rights site.
Water Rights & Land Ownership
Roosevelt County is largely the Fort Peck Indian Reservation (Assiniboine and Sioux Tribes), with the Missouri River forming the southern border. Wolf Point is the county seat; Poplar is the Tribal HQ. The Poplar River drains north-to-south through the county into the Missouri. The Fort Peck-Montana Water Compact sets reserved Tribal water rights that are senior to most state-administered priority dates on reservation parcels.
Active state-administered rights pulled live from DNRC WRQS on 2026-06-01. Roosevelt spans three basins: 40Q (Poplar R.), 40R (Big Muddy / NE Missouri), 40S (Lower Missouri side). Fort Peck Tribal compact rights are administered by the Tribes and are not fully reflected in WRQS.
Roosevelt County Watershed Map
Search Roosevelt County water rights
- Water right format:
- 40Q 12345 00 (Poplar) · 40R (Big Muddy) · 40S (Lower Missouri side).
- Primary basins:
- 40Q Poplar R · 40R Big Muddy · 40S Lower Missouri side.
- Fort Peck Compact:
- Federally-reserved Tribal water rights senior to most state priorities on reservation parcels; administered by Fort Peck Tribal Water Resources, not state WRQS.
- International note:
- Poplar R. and Big Muddy Cr. headwaters extend into Saskatchewan — apportionment under Boundary Waters Treaty.
- DNRC regional office:
- Glasgow Regional Office, 406-228-2561.
- Clerk & Recorder:
- Roosevelt County, 406-653-6250.
Irrigated Acres — USDA Census
Roosevelt County reported 12,003 irrigated acres in the 2022 USDA Census of Agriculture, down from 24,263 in 2017 — a change of −12,260 acres (−50.5%). These are acres that actually received irrigation in the census year, not all land equipped for irrigation.
Source: USDA 2022 Census of Agriculture, Table 10 (irrigated land, acres). See the Measuring Montana Moisture overview →
Quick links
Data sources: Montana DNRC, MSL/DOR Cadastral, MBMG GWIC. Fort Peck Tribal compact rights administered separately from state. Informational only.