Unit 70

The Shirley Mountains form the dominant northern landmark and serve as a major glassing platform and mule deer migration corridor. Fossil Ridge and Moss Agate Ridge provide secondary vantage points for surveying the basins below. The Breaks—a series of canyons and rimrock features including Smith Creek Rim and Dry Creek Rim—offer natural breaks in terrain valuable for understanding deer movement.

Grinnell Lake, Hi Allen Spring, and the scattered small reservoirs (Rosebud, Dry, Red, and others) mark reliable water sources and anchor hunting strategy. These landmarks, combined with named draws and creeks like Sips Creek and Lost Creek, provide solid navigation reference without requiring GPS.

Elevations span from mid-6000s in the basin floors to just over 9,100 feet on the high ridges, creating distinct habitat bands. Lower elevations are dominated by sagebrush and bitterbrush with scattered juniper and ponderosa; mid-elevation slopes transition to more consistent tree cover with aspen draws and conifer patches. Upper ridges and mountains support denser forest.

The sparse-to-moderate timber distribution means most of the unit remains open country—sagebrush parks, meadows, and grassy benches—making glassing effective and travel relatively unobstructed. This openness is key: mule deer use the ridges and timbered pockets for cover but move across open flats to feed.

The unit maintains limited organized access—298 miles of roads totaling a sparse network suitable for stock travel and high-clearance vehicles rather than passenger cars. Wyoming Highway 487 (Medicine Bow-Rawlins corridor) and U.S. 30 provide easy entry from towns; from there, hunters transition to county roads and rough BLM tracks. This creates moderate pressure along main corridors but many backwater areas see light use.

The Shirley Basin area and ridges accessible from Hanna experience more attention; the southern Breaks and draws off the county roads are less crowded. The landscape is big enough to swallow pressure with minimal effort—avoid main staging areas and the basin near populated places, move into the ridges and draws.

Unit 70 forms a large, irregularly shaped block anchored by the town of Medicine Bow to the southeast and Hanna to the north, with boundaries following U.S. 30, Wyoming highways 72 and 77, and county roads defining a landscape between the North Platte River system and the uplands. The unit's heart is Shirley Basin—a productive mule deer area—with the Medicine Bow Breaks marking the southern tier and the Freezeout and Shirley Mountains rising along the north and western flanks. This configuration captures the transition zone between prairie and mountain, roughly 40 miles long and 25 miles wide at its broadest.

Moderate water availability supports decent hunting potential in semi-arid terrain. The North Platte River forms the northern boundary and receives flow from multiple drainages including Canyon Creek and Pathfinder Reservoir. Numerous springs—Barrel, Red, Withrow, Dyer, and others—are scattered throughout the unit; small reservoirs like Rosebud, Dry, Red, and Section 20 hold seasonal water.

Sips Creek, Lost Creek, and Twin Springs Creek provide perennial flow in their drainages. During early season, high-elevation sources are reliable; by late season, hunting pressure concentrates near persistent water in lower basins. Understanding this water network is essential for deer location and movement prediction.

Mule deer are the primary quarry; whitetails inhabit riparian draws and canyon bottoms but are secondary. Early season favors high-elevation glassing—glass the Shirley and Freezeout mountains and ridge systems during morning and evening, watching for deer on open benches and in aspen groves. Mid-season, concentrate on transitional zones where deer move between high summer range and lower basins as temperatures cool.

Late season shifts to basin hunting near reliable water (the small reservoirs and springs) where deer concentrate. Terrain complexity is moderate: the rolling basins and scattered ridges allow efficient glassing, but successful hunting requires patience to spot deer in this open, sparse-timber environment. Plan water access carefully and hunt the edges of timbered pockets where deer move between cover and feeding areas.