GMU 12B Unit 12B — Flagstaff
The Kaibab's wintering country — lower, sparser, and capable of throwing an absolute giant.
North Kaibab — Marble Platform & House Rock Valley · Last reviewed 2026-07-12
Area
1,120
sq mi
Public land
90%
approx.
Elevation
3,200–8,800
feet
Motorized
moderate
access
Overview
Unit 12B wraps the eastern and lower flanks of the Kaibab Plateau, running out across House Rock Valley and the Marble Platform toward Marble Canyon. It is primarily mule deer wintering range: bucks migrate down off the 12A plateau into 12B as fall snow arrives. Deer densities are lower than the plateau, but in the right conditions the unit produces monster bucks that rival anything off the Kaibab or the Strip. Tags are hard to draw and reward patient, ground-covering hunters.
Terrain
Steps down from the timbered plateau rim (~8,800 ft) through pinyon-juniper benches into the broad, open sagebrush expanse of House Rock Valley and the Marble Platform near 3,200 ft along the Colorado River.
Cover: Ponderosa and pinyon-juniper on the upper benches; extensive sagebrush flats, blackbrush and grassland across House Rock Valley and the Marble Platform.
Landmarks: House Rock Valley · Marble Platform · Marble Canyon / Colorado River · Saddle Mountain · Vermilion Cliffs
Access
Mostly BLM and Kaibab NF with good vehicle access across the valley. The Colorado River / Marble Canyon forms the eastern boundary — the Navajo Nation beyond it is tribal land and NOT open to general AZGFD hunting. Grand Canyon NP borders the southwest and is closed. State Trust parcels need an Arizona recreation permit.
Managers: USFS Kaibab NF (North Kaibab RD), BLM (House Rock Valley, Vermilion Cliffs NM), Grand Canyon NP (closed to hunting), Navajo Nation (tribal, closed — east of the Colorado River), AZ State Trust
Access points: House Rock Valley Road (BLM 1065) off Hwy 89A · Hwy 89A (Jacob Lake to Marble Canyon) · FR 8910 / Saddle Mountain access · Buffalo Ranch / House Rock roads
Species notes
Mule Deer
common trophyWinter range for Kaibab Plateau bucks — lower density and lower average success (~41%) than 12A, but capable of producing genuine giants when deer migrate down with the snow.
- →Time late hunts to the migration — deer pour off the 12A plateau into these benches and valley as snow builds
- →Glass sagebrush flats, draws and pinyon-juniper edges from vantage points
- →Cover lots of country; bucks are scattered and low-density
- →Watch the transition benches between timber and open valley
Pronghorn
limited qualityA small pronghorn population on the open flats of House Rock Valley — few tags, few animals, but they inhabit classic glassable antelope country.
- →Glass the wide-open House Rock Valley flats
- →Spot-and-stalk across the sage and grassland
- →Check water sources in dry conditions
Bighorn Sheep
limited trophyDesert bighorn hold the rugged Marble Canyon breaks and cliff country along the Colorado River — a rare, coveted tag.
- →Hunt the canyon rims and side-canyon rock faces above the river
- →Long-range glassing of ledges and benches at first light
- →Prepare for steep, foot-only canyon terrain
Pro tips
- →This is a wintering unit — bank on the late-season migration to bring the big bucks down.
- →Snow up on the plateau is your friend; it fills 12B with deer.
- →Glass, glass, glass the sage flats and benches — density is low and success comes from spotting.
- →Know the Colorado River line: the Navajo Nation across it is closed tribal land.
- →Dirt roads turn to gumbo when wet — pack recovery gear and don't get stuck miles out.
Watch out for
- !Navajo Nation (east of the Colorado River) is tribal land, closed to general AZGFD hunting — do not cross or hunt it.
- !Grand Canyon National Park (southwest boundary) is closed to hunting.
- !State Trust parcels require an Arizona State Land recreation permit.
- !Low deer density — an early/mild year with no migration can be tough.
- !Remote desert country: carry ample water, and mud/recovery gear for dirt roads.
Logistics
Sparse services — Marble Canyon and Jacob Lake offer minimal fuel and supplies; resupply in Page, Fredonia or Kanab. Dispersed camping on BLM and Kaibab NF. House Rock Valley Road and side tracks are dirt and turn greasy when wet — carry recovery gear.
Nearest towns: Marble Canyon, Jacob Lake, Fredonia, Page, Kanab, UT
Seasons & regulations
This page carries no season dates or regulations. Get current rules from the official Arizona sources:
Research sources: AZGFD — GMU 12B · Outdoors International — The Kaibab: Units 12A East, 12A West & 12B · Arizona Strip Guides — Unit 12B Mule Deer
FAQ
- How big is GMU 12B in Arizona?
- GMU 12B (Unit 12B — Flagstaff) covers about 1,120 square miles, ranging from roughly 3,200 to 8,800 feet in elevation. Area is computed from the unit boundary polygon.
- How much public land is in GMU 12B?
- Approximately 90% of the unit is public land. Primary managers: USFS Kaibab NF (North Kaibab RD), BLM (House Rock Valley, Vermilion Cliffs NM), Grand Canyon NP (closed to hunting), Navajo Nation (tribal, closed — east of the Colorado River), AZ State Trust. Always verify ownership boundaries on the ground.
- What species does the catalog list for GMU 12B?
- Mule Deer, Pronghorn, Bighorn Sheep. For seasons, tags, and regulations, use the official Arizona agency resources linked on this page — this page carries no regulatory information.
Put GMU 12B on your map.
Boundary lines, public/private ownership, topo, and offline maps for this unit — in Baseline Maps, free for 14 days.