How big is GMU 23 in Colorado?

GMU 23 (GMU 23 — Rio Blanco/Garfield Co.) covers about 424 square miles, ranging from roughly 5,400 to 9,500 feet in elevation. Area is computed from the unit boundary polygon.

What species does the catalog list for GMU 23?

Rocky Mountain Elk, Mule Deer, Pronghorn, Black Bear. For seasons, tags, and regulations, use the official Colorado agency resources linked on this page — this page carries no regulatory information.

GMU 23 GMU 23 — Rio Blanco/Garfield Co.

OTC bull elk, quality mule deer, and a bonus pronghorn tag in the sage-and-oakbrush breaks below the Flat Tops

Northwest Colorado — White River elk country west of the Flat Tops · Last reviewed 2026-07-12

Bull elk standing at the edge of dark timber

Area

424

sq mi

Public land

42%

approx.

Elevation

5,400–9,500

feet

Motorized

moderate

access

Overview

GMU 23 sits in Rio Blanco and Garfield Counties between Meeker and Rifle, forming the lower western flank of Colorado's White River elk complex — home to the largest migratory elk herd in North America. The unit runs from the Grand Hogback and pinyon-juniper mesas near the Colorado River divide up into oakbrush and aspen benches on the White River National Forest fringe, bounded west by CO-13/789 toward the Piceance country. Elk carry the harvest by a wide margin, mule deer are strong and genuinely quality, and a small pronghorn herd works the open sage. Bull elk here are over-the-counter for second and third rifle seasons, so this is an opportunity unit for elk with the room and volume to match.

Terrain

Stair-stepping foothill-to-mountain country — low pinyon-juniper mesas and sagebrush parks along the river divides climbing through oakbrush and aspen benches toward the White River National Forest and the western edge of the Flat Tops.

Cover: Pinyon-juniper and big sagebrush on the dry lower breaks, dense Gambel oakbrush on the mid-slopes, aspen stringers and mixed conifer on the higher benches, with grassy parks and creek-bottom willow.

Landmarks: Grand Hogback · White River-Colorado River divide · Buford-Newcastle Road (FSR 245/CR 17) · Piceance country to the west · oakbrush winter-range benches

Access

A true mixed-ownership unit. National-forest and BLM blocks on the higher and northern ground are interlaced with substantial private ranch bottoms, especially the productive low-elevation winter range along the White River and lower creeks. Public access is real but demands map work to avoid landlocked BLM and private inholdings. State Trust Land is generally closed unless enrolled in the Public Access Program. Much of the best low elevation is private, so concentrate on public benches, the forest fringe, and travel corridors.

Managers: BLM (White River Field Office), USFS White River NF, private ranch, Colorado State Trust Land (generally closed unless in CPW Public Access Program)

Access points: BLM and county-road network off CO-13 and Rio Blanco/Garfield county roads · Buford-Newcastle Road (FSR 245/CR 17) into the White River NF fringe · FSR 250 and upper-bench forest access on the east side

Species notes

Rocky Mountain Elk

abundant opportunity

The marquee species and the backbone of the harvest — part of the White River herd, the largest migratory elk herd in North America. Bull elk are over-the-counter for second and third rifle seasons, making this a genuine opportunity unit with high harvest volume. Success runs modest, which is the trade-off for OTC access and pressure.

→Hunt the oakbrush-to-aspen transitions and dark timber pockets where elk bed off the sage and mesa parks
→Glass sagebrush parks and grassy benches at dawn and dusk
→During the rut, work timbered draws and wallows with calling
→Later rifle seasons: intercept migration as snow pushes elk down off the Flat Tops fringe toward lower winter range
→Get away from road corridors and know exactly where private begins

Mule Deer

common quality

A strong, fully limited-draw mule deer unit and part of northwest Colorado's big-buck reputation. Deer share the sage-oakbrush-aspen mosaic with elk and follow the same seasonal push off the high benches into winter range; much of the best low-elevation deer ground along the White River sits on private.

→Glass sagebrush and oakbrush edges at first and last light
→Bucks hold in oakbrush pockets and aspen stringers through midday
→Rut and migration timing put mature bucks on the move into lower country
→Prioritize public benches and breaks with good visibility over crowded roads

Pronghorn

limited opportunity

A small pronghorn herd uses the open sagebrush parks and grassland flats of the lower western unit. Modest harvest with fair success reflects a small, tightly managed population — a bonus draw tag rather than a primary reason to hunt GMU 23.

→Glass the open sage flats and parks for scattered bands
→Use terrain and the sparse cover to close the distance
→Water sources and open feeding areas concentrate animals

Black Bear

common opportunity

Black bears work the oakbrush and aspen country, especially where acorns and serviceberry are heavy in early fall — classic mountain-shrub bear habitat across the White River units.

→Hunt oakbrush thickets and berry patches in early fall
→Glass feeding bears at dawn and dusk on shrubby slopes
→Often an incidental opportunity while elk or deer hunting

Pro tips

→This is an OTC elk unit for 2nd/3rd rifle — expect company and hunt away from the road network to find quiet elk
→Nail down public-vs-private with a GPS layer; ranch bottoms along the White River hide the best low winter range
→Elk and deer both key on the oakbrush/aspen-to-sage transition — hunt the edges
→Time later hunts to migration; a good snow turns a slow unit into a great one
→Watch the clay roads — get out ahead of storms or plan to sit them out

Watch out for

!Private ranch inholdings and landlocked public — verify boundaries carefully
!State Trust Lands generally closed unless enrolled in the Public Access Program
!OTC elk seasons bring crowding on accessible public ground
!Clay/dirt roads become impassable when wet
!Early-season fire danger in dry years

Logistics

Meeker and Rifle are the practical hubs for fuel, lodging, groceries, and processing, with Rifle on I-70 for easy staging. Backcountry roads are dirt and clay that turn greasy and impassable when wet, so carry chains, recovery gear, and watch the weather. Cell coverage fades quickly off the main corridors.

Nearest towns: Meeker, Rifle, New Castle, Silt

Nearby units

GMU 33 · GMU 33 — Garfield/Rio Blanco Co. GMU 24 · GMU 24 — Rio Blanco/Garfield Co. GMU 211 · GMU 211 — Moffat/Rio Blanco Co. GMU 12 · GMU 12 — Moffat/Routt/Rio Blanco Co.

Seasons & regulations

This page carries no season dates or regulations. Get current rules from the official Colorado sources:

Research sources: CPW Big Game Hunting Statistics · CPW 2024 Big Game Regulations — OTC bull elk units (White River herd) · CPW Hunting Atlas — GMU boundaries and public access · USFS White River National Forest

FAQ

How big is GMU 23 in Colorado?: GMU 23 (GMU 23 — Rio Blanco/Garfield Co.) covers about 424 square miles, ranging from roughly 5,400 to 9,500 feet in elevation. Area is computed from the unit boundary polygon.
How much public land is in GMU 23?: Approximately 42% of the unit is public land. Primary managers: BLM (White River Field Office), USFS White River NF, private ranch, Colorado State Trust Land (generally closed unless in CPW Public Access Program). Always verify ownership boundaries on the ground.
What species does the catalog list for GMU 23?: Rocky Mountain Elk, Mule Deer, Pronghorn, Black Bear. For seasons, tags, and regulations, use the official Colorado agency resources linked on this page — this page carries no regulatory information.

Put GMU 23 on your map.

Boundary lines, public/private ownership, topo, and offline maps for this unit — in Baseline Maps, free for 14 days.

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