Unit 20A

Several distinctive buttes serve as navigation anchors: Rattlesnake Butte, Twin Butte, and Thunder Hawk Butte are the most prominent features for glassing and orientation. The Missouri River itself forms a major boundary and drainage, with Thunder Hawk Creek and Archambault Creek providing reliable water corridors worth exploring. Mallard Lake and McIntosh Lake offer water source reference points.

The Kline Buttes form a low range useful for navigation. These landmarks are widely spaced across the unit, emphasizing the vast, open character—hunters should plan routes between water and butte systems rather than expecting dense landmark clusters.

This is entirely low-elevation plains country, ranging between roughly 1,600 and 2,700 feet with a median around 2,100 feet. The terrain is predominantly open grassland with minimal forest—the scattered buttes rise as low rocky breaks offering vantage points amid otherwise featureless prairie. Sagebrush and short-grass prairie dominate the habitat, with willows and cottonwoods concentrated along creek bottoms and the Missouri River corridor.

The buttes—Rattlesnake, Elk, Twin, and Thunder Hawk among others—punctuate the landscape as natural glassing points and hunting benches. This grassland-focused unit favors hunters comfortable working open country where spotting is possible but cover is limited.

The unit faces a critical access constraint: 96% of land is private. With only 3.6% public land, hunting success depends entirely on securing permission or accessing public reservoirs and river corridors. Road density of 0.83 miles per square mile means fair connectivity—you can generally reach most areas via county roads and ranch roads—but access permission remains the bottleneck.

This low public-land percentage concentrates pressure where access exists, likely around known reservoirs and river breaks. Early-season pressure tends to be moderate; by mid-season, hunters concentrate wherever permissions are established.

Unit 20A sprawls across 2,530 square miles of the northern Great Plains, encompassing the region between the Missouri River breaks and the rolling prairie landscape of northwestern South Dakota. The unit's relatively flat character and enormous size make it a sprawling region where distances between water and hunting zones require planning. Small towns like McLaughlin, Morristown, and Thunder Hawk dot the edges and provide staging points.

The landscape transitions gradually from open grassland to Missouri River breaks—a subtle but important distinction for hunting strategy and terrain navigation across this vast expanse.

Water is the unit's strongest feature. Thunder Hawk Creek, Archambault Creek, Cottonwood Creek, and Meadow Creek run year-round through the unit, offering reliable water and travel corridors. The Missouri River dominates the eastern boundary and serves as a major water source.

Multiple reservoirs and lakes—Mallard Lake, McIntosh Lake, Tatanka Lake, Spring Lake—provide additional options. Creeks often carve shallow valleys that concentrate game and offer hidden movement routes through otherwise open country. Water access is abundant enough to allow hunters to plan based on game location rather than water scarcity, a significant advantage in plains hunting.

Unit 20A holds mule deer, white-tailed deer, and occasional mule deer populations across its prairie and break country. Mule deer favor the buttes and creek-bottom cover; white-tailed deer inhabit the river breaks and willow corridors. Early season finds deer scattered across open grassland; focus glassing from buttes at dawn and dusk.

As season progresses, concentrate on creek bottoms and river breaks where cover provides security. The vast, open character means you'll spot animals from distance but must plan careful stalks—limited cover makes the approach the challenge. Water sources concentrate game, especially later in the season.

Timing your presence to wind and light is critical in this open terrain.