Colorado Unit 851 Hunting Information

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Overview of CO GMU 851 Hunting Facts

Located in southern Colorado within the boundaries of Costilla and Las Animas counties, Unit 851 is one of those units that hunters dream about. It has been featured on several television hunting shows and its legendary success has everybody talking. The majority of the unit is private, but the Bosque del Oso State Wildlife Area is the tag to draw. Tags are drawn either for use exclusively in Bosque del Oso SWA or hunting the rest of the unit outside of Bosque del Oso SWA. Also, not all seasons are available for both tags.

Table of Contents

CO Unit 851 Species Hunting Info

INFO: Mule Deer Hunting in Colorado Unit 851

Colorado Unit 851 has a predominantly warm climate and is known for being a heavily-used wintering ground for elk and mule deer. The public’s restricted access from hunting in the Bosque del Oso SWA helps to manage the herd by limiting the number of hunters that can even step foot in the area. The bucks are able to fully mature, improving the odds of nabbing a monster muley!
SUCCESS RATES for Mule Deer Hunting in Colorado Unit 851
5 Year Estimated Average for Deer
Bosque del Oso SWA ONLY Units 85/851 EXCEPT Bosque del Oso SWA
Archery 80% 60%
Muzzleloader 60% 55%
Early Rifle 50% no tag
2nd Rifle 80% 50%
3rd Rifle no tag 40%
Mule Deer TROPHY QUALITY for Unit 851 Colorado
Average Quality 150″ – 170″
Trophy Potential 170″ +
Buck to Doe Ratio 35:100
Colorado Unit 851 Mule Deer Hunting FORUM COMING SOON!

INFO: Elk Hunting in Colorado Unit 851

Unit 851 is a dignified Trophy Elk Unit that is undeniably a top choice for hunting in Colorado. The limited access of the Bosque del Oso SWA helps keep pressure off of the wildlife and restricts excessive disturbances. Elk return to this area every year as part of their wintering pattern. The abundance of vegetation and water sources sustain elk populations throughout the winter. If you are not planning to hunt the Bosque del Oso SWA, elk tags are available OTC for archery, 2nd rifle and 3rd rifle seasons.
SUCCESS RATES for Elk Hunting in Colorado Unit 851
5 Year Estimated Average for Deer
Bosque del Oso SWA ONLY Units 85/851 EXCEPT Bosque del Oso SWA
Archery 32% 18%
Muzzleloader 25% 17%
Early Rifle 60% 30%
2nd Rifle 70% 25%
3rd Rifle 60% 20%
3rd Rifle 50% 25%
Elk TROPHY QUALITY for Unit 851 Colorado
Average Quality 340″ – 370″
Trophy Potential 370″ +
Buck to Doe Ratio 21:100
Colorado Unit 851 Elk Hunting FORUM COMING SOON!

INFO: Antelope Hunting in Colorado Unit 851

Antelope hunting in Unit 851 Colorado may not be considered as a favorite pastime to the hunting crowd. However, bucks are harvested from this unit every year. If you’re deer or elk hunting Unit 851 except on Bosque del Oso SWA, an OTC archery tag is a great combination for your big game hunt.
Buck to Doe Ratio
Colorado Unit 851 Antelope Hunting FORUM COMING SOON!

Available Hunts for Colorado Unit 851

No Available Hunts

Unit 851 Hunting Information Video


Cities Near CO Unit 851


Colorado Unit 851 Topo Map

Total Acreage: 280,000 acres over 438 square miles

Total Public Land: 36,000 acres or 12%

Land Ownership Mix: 88% Private; 12% Public; USFS: 2,112 acres; State: 30,912 acres; Other Govt Owned: 3,712 acres

Species Common in the Area: Black Bear, Elk, Mule Deer, Moose, Pronghorn

Elevation Variance: 6,025 ft. to 14,049 ft.

Terrain Difficulty Overall: Mild to Moderate

Land Coverage/Vegetation: Land cover includes 56% evergreen forest, 20% shrub/scrub, and 10% grassland

Unit 851 Boundaries: (Costilla, Las Animas County Colorado) bounded on North by West Fork of Purgatoire River, North Fork of Purgatoire River and Colorado 12; on East by Interstate25; on South by NM; on West by Sangre de Cristo Divide


Lay of the Land in CO Unit 851


Terrain in GMU 851 CO

As is the case of most Colorado GMU’s, the terrain is a combination of many geographic features. In Bosque del Oso SWA along with areas near Culebra Peak, you will find heavily forested mountains, rocky mesas, and sharp canyons. Unit 851 also contains miles of scrub oak-covered foothills and drainages that are known to hold pressured wildlife. There are tracts of meadows containing shrubbery of forbs, grass varieties, and cactus.

Vegetation in GMU Unit 851 CO

In the high elevations, you will find coniferous forests of evergreen varieties such as spruces and firs. Blended with them are aspen groves. A little further down in elevation, there are ponderosa forests, pinyon-juniper fields, and riparian vegetation such as cottonwoods, which grow near water sources. In the lowest of elevations, expect to see shrubbery of forbs, grass varieties, and cactus.

Access Points in CO GMU 851

CO-12 winds along the northern border of the unit east to west from Trinidad. IH-25 makes the eastern boundary line separating Unit 851 and Unit 140. The southern portion of the unit is bordered by New Mexico. Public access roads are minimal in this unit due to the small amount of public land that is even available to hunt. The Bosque del Oso SWA has strict rules regarding motorized vehicles and being granted access unless you hold a tag designated for the SWA.