Honest Cattle · Lewis and Clark County
Lewis and Clark County Water Rights
Water Rights & Land Ownership
Lewis and Clark is the capital county — Helena is the state capital, sitting in the Helena Valley with the Big Belts to the east and the Continental Divide to the west. The Missouri River flows through the county into Canyon Ferry. Augusta and the Sun River drainage occupy the NW corner. The county straddles the Continental Divide: most of the county drains to the Missouri, but the NW corner drains west into the Blackfoot / Clark Fork system. Over 22,000 active rights.
Active rights pulled live from DNRC WRQS on 2026-06-01. Lewis & Clark spans eight basins: 41I (Sun R.), 41J (Missouri above Sun), 41K (Marias edge), 41QJ (Smith side), 41U (Dearborn), 76F/76G (Clark Fork tribs west of divide), 76J (Blackfoot).
Lewis & Clark County Watershed Map
Search Lewis & Clark County water rights
- Water right format:
- 41I 12345 00 (Sun) · 41J (Missouri above Sun) · 76J (Blackfoot, W of divide).
- Primary basins:
- 41I Sun · 41J Missouri · 41K/41QJ/41U Missouri tribs · 76F/76G/76J Clark Fork-Blackfoot W of divide.
- Continental Divide:
- NW corner west-of-divide parcels drain to Clark Fork (76 series) — different administrative basin and downstream call structure.
- Canyon Ferry context:
- USBR storage just south in Broadwater — Missouri main-stem rights coordinated with project releases.
- DNRC regional office:
- Helena Regional Office, 406-444-6999.
- Clerk & Recorder:
- Lewis and Clark County, 406-447-8334.
Irrigated Acres — USDA Census
Lewis and Clark County reported 47,709 irrigated acres in the 2022 USDA Census of Agriculture, down from 48,209 in 2017 — a change of −500 acres (−1.0%). 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, USBR. Active rights pulled live from DNRC WRQS on 2026-06-01. Informational only.