Unit 400

The Missouri River and Marias River form the unit's dominant geographic features, offering both navigation corridors and reliable water sources. Rowe Bench and Dobie Ridge provide modest elevation gains useful for glassing the surrounding prairie. Notable reservoirs including Fowler, Pugsley, and Romain offer watering holes and navigation reference points across the flatter country.

Goose Bill Butte and Conrad Butte serve as subtle but recognizable skyline markers for orientation. The Loma Ferry crossing on the Missouri and the breaks near Fort Benton anchor the southern portion. Power Coulee, Willow Creek, and Snake Creek drainages cut through the terrain and funnel movement for both hunters and game.

The entire unit sits in low-elevation prairie-grassland terrain ranging from roughly 2,500 to 3,800 feet, creating a consistent, rolling landscape without the dramatic elevation changes found in higher mountain units. Sparse timber—primarily cottonwoods—follows river bottoms and major drainages, while the dominant terrain remains open sagebrush prairie and native grasslands. The Marias and Missouri river breaks cut through the prairie creating deep coulees with steeper slopes and scattered juniper.

Vegetation transitions are subtle, with slightly more vegetation density in the breaks country compared to the open flats. This is primarily a grassland ecosystem shaped by water availability and soil type rather than elevation.

Over 2,200 miles of road network thread through this lower-elevation unit, with US Highway 2 providing primary access from the west and secondary routes branching through the breaks. The unit is accessible from Shelby, Fort Benton, and Chester, with established camping and staging areas near populated centers. The straightforward terrain and extensive road network mean most pressure concentrates along highway corridors and near reservoirs.

The deeper breaks country away from maintained roads sees less hunting pressure despite being reachable. Terrain complexity is low, making navigation simple for most hunters, though the coulees can be confusing once away from obvious landmarks.

Unit 400 encompasses the low-elevation country spanning four north-central Montana counties between Shelby on the west and Fort Benton on the south, bounded by Interstate 15, US Highway 2, and the Marias and Missouri rivers. The unit is bounded north and west by Highway 2, east by the Hill-Liberty county line and Marias River, south by the Missouri River and Route 80, and includes the Fort Benton area. The landscape sits at relatively modest elevation in the transition zone between the higher mountain ranges to the west and the northern Great Plains.

This is classic prairie-breaks country with historical significance tied to the Missouri River corridor.

The Missouri and Marias rivers anchor the unit's water system, providing year-round flow and defining the breaks topography. Numerous smaller drainages including Willow Creek, Snake Creek, and Power Coulee create reliable water sources through the prairie. Scattered springs like McBridy Spring supplement water availability in the breaks country.

Multiple irrigation reservoirs—Fowler, Pugsley, Romain, Gillespie, and others—dot the landscape, primarily serving agricultural purposes but providing stock water. The irrigation canal network (P, G, F, K ditches) indicates developed water infrastructure. Water availability is moderate to good, though seasonal flow varies; the river systems remain reliable through hunting season.

Unit 400 holds elk, mule deer, whitetail deer, and mountain lion in habitat defined by prairie grasslands and river breaks. Elk typically inhabit the cottonwood-lined breaks and deeper coulees where cover is available, moving between the river bottoms and surrounding prairie seasonally. Mule deer favor the open prairie and sagebrush flats with access to breaks and water, while whitetails concentrate in the riparian timber and thicker brush.

Early season hunting targets open country glassing from benches and ridges; rut hunting focuses on the breaks and river bottoms where cover attracts deer. Mountain lion hunting follows coulee systems and drainage draws where deer concentrate. Water sources, particularly the Missouri River and major creeks, drive daily movement patterns.