Unit 25A, Alaska

Unit 25A spans five ecological zones from north to south: Arctic Ocean coastal plain tundra (North Slope), rolling tussock tundra of the foothills, alpine tundra and glaciated peaks of the Brooks Range (summits to 9,000 ft), forest-tundra transition zone, and boreal forest along the southern drainages (Chandalar, Sheenjek, Coleen, Christian rivers). The Brooks Range runs east-west through the center of the unit in a band roughly 75 miles wide. The ANWR coastal plain — the calving grounds of the Porcupine Caribou Herd — lies north of the mountains. River systems include the Coleen, Old Crow, Sheenjek, East Fork Chandalar, and Christian rivers. Terrain is extremely rugged with no maintained infrastructure.

Primary access is by charter aircraft (floatplane or Super Cub on tundra/gravel bars) from Fairbanks (~250 miles southwest), Fort Yukon, Arctic Village, Deadhorse (Prudhoe Bay), or Kaktovik. There are no roads, established trails, or facilities within ANWR's 19.64 million acres. The Dalton Highway (Haul Road) touches only the extreme western boundary of the unit near the Arctic NWR western edge; hunters may legally hike from the road into the unit but must stay at least 5 miles from the highway to discharge firearms. All aircraft landings occur on gravel bars, tundra, or lakes. Float trips on the Sheenjek, Coleen, and Canning rivers are also used. Public lands: Arctic National Wildlife Refuge (19.64M acres, USFWS), Venetie Tribal Lands (private — Gwichin; access restrictions apply), and state lands. Estimated 92-95% of the unit is federally managed public land.

North Slope coastal plain: sedge-cottongrass tussock tundra, polygon wetlands, shrub tundra. Arctic foothills: tussock tundra, willow/alder shrub, wet sedge meadows. Brooks Range: alpine fellfield, krummholz (dwarf birch/willow), talus slopes, glacial cirques. Southern foothills and valleys: tall shrub tundra (willow, alder), white and black spruce forest with bog complexes, riparian cottonwood stands. No agriculture. Permafrost underlies the entire unit.

The Porcupine Caribou Herd (PCH) is the dominant migratory force in Unit 25A. The herd calves on the ANWR coastal plain (May–June), then disperses south and west through the Brooks Range passes during summer before migrating east into Canada's Richardson Mountains for winter. The herd's movements are circuitous and year-to-year unpredictable — hunters cannot count on caribou being present in a specific location. 2025 PCH population estimate: ~143,000 (down from a 2017 peak of 218,000; significant decline in adult survival 2023-2025). The Central Arctic Caribou Herd (est. 26,600 in 2025, down from a 2010 peak of 68,400) uses the western fringe of Unit 25A near the Haul Road and GMU 24A. Dall sheep are year-round residents of the Brooks Range alpine ridges. Grizzly bears range throughout the unit following caribou migration and berry/salmon cycles. Moose inhabit riparian willow corridors of the Chandalar and Sheenjek drainages. Wolves follow caribou migration routes.

SUBSISTENCE: Unit 25A is subject to dual federal/state subsistence management. On federal public lands (ANWR and other federal lands), federally qualified users (Alaska rural residents) have priority for subsistence hunting. The Federal Subsistence Board manages wildlife on federal lands; non-rural residents and non-residents cannot take wildlife for subsistence on federal public lands. The Arctic Village Sheep Management Area within Unit 25A is closed to non-federally qualified users for sheep take due to conservation concerns and unresolved user-group conflicts — this closure applies on public lands. NON-RESIDENT RESTRICTIONS: Non-residents hunting Dall sheep must be accompanied by a licensed Alaska guide or a resident who is a direct family relative (spouse, parent, sibling, or child) — this is a state law requirement. Non-residents hunting brown/grizzly bear must also be accompanied by a licensed guide or qualified resident relative. Non-residents hunting moose must complete the ADF&G Nonresident Moose Hunter Orientation course before hunting; proof required in field. AIRCRAFT: Use of aircraft to access sheep hunting areas or transport harvested sheep is prohibited in Unit 25A except for flights into and out of Arctic Village and Kaktovik airports. DHCMA: The western portion of Unit 25A along the Dalton Highway falls within the Dalton Highway Corridor Management Area (DHCMA); additional restrictions apply including a 5-mile no-discharge buffer from the road. SHEEP ORIENTATION COURSE: Beginning July 2026, all hunters in general harvest ticket sheep hunts (Aug 10–Sep 10) must complete a state-approved hunter orientation course. MUSK OX: ANWR has a small reintroduced musk ox population; draw permit hunts have been extremely limited and are primarily subsistence-only or not currently available for sport hunters in Unit 25A. Check current ADF&G draw supplement for any RS or RX hunts.