GMU 91 GMU 91 — Sedgwick Co.
A small, deer-rich plains unit built on South Platte river bottoms — whitetail and mule deer
Northeastern Colorado plains — South Platte river-bottom country (Logan County) · Last reviewed 2026-07-12
Area
77
sq mi
Public land
5%
approx.
Elevation
3,600–4,300
feet
Motorized
moderate
access
Overview
GMU 91 is a compact unit of roughly 77 square miles on the northeastern plains of Logan County, built around the South Platte River corridor. It stacks three habitats — irrigated cropland, sandsage and mid-grass prairie, and cottonwood riparian bottoms — that together make it one of the better deer producers in the corner despite its small size. Whitetail thrive in the wooded river bottoms and mule deer work the sage and ag edges, while elk are only an incidental transient. The near-total catch is access: the great majority of GMU 91 is private land with very limited public entry.
Terrain
Low-relief High Plains centered on the South Platte river bottom — flat irrigated crop ground and sandsage prairie broken by the wooded, braided river corridor and its draws and oxbows.
Cover: Cottonwood-and-willow riparian along the South Platte, sandsage and mid-grass prairie on the uplands, and irrigated corn and row-crop fields, with brushy fencelines and shelterbelts.
Landmarks: South Platte River corridor · Cottonwood river bottoms · Logan County farm country · irrigated crop circles · Sterling area
Access
The majority of GMU 91 is private land and public access is very limited. A handful of small state wildlife areas and scattered state sections offer the only walk-in opportunity; otherwise plan on landowner permission, a trespass arrangement, or an outfitter to reach the productive river bottoms and ag edges. Colorado State Trust lands here are NOT open to hunting unless enrolled in CPW's Public Access Program.
Managers: private farm and ranch, CPW State Wildlife Areas (small parcels), State Trust Land (closed)
Access points: South Platte river-bottom SWAs (small parcels) · county section roads through the farm ground · highway frontage near Sterling
Species notes
Whitetail Deer
common qualityThe defining hunt in GMU 91 — whitetail concentrate in the cottonwood river bottoms and wooded draws of the South Platte, and this small unit posts a strong deer harvest for its size. A classic eastern-plains riparian whitetail hunt, with the caveat that the best bottoms are private.
- →Hunt the cottonwood river bottoms, oxbows, and wooded draws where whitetail bed and travel.
- →Time the rut, which on the eastern plains can run from late October into December.
- →Access is everything — the river bottoms are private, so secure permission or hunt the small SWAs along the corridor.
Mule Deer
common opportunityMule deer share the unit, working the sandsage prairie, shelterbelts, and crop edges away from the river while whitetail hold the bottoms. Buck success runs moderate. Together the two deer species make GMU 91 a deer-first unit.
- →Glass the sandsage flats, shelterbelts, and ag edges on the uplands away from the river.
- →Hunt cover-to-crop transitions at first and last light.
- →Line up private access early; public ground is a few small parcels only.
Rocky Mountain Elk
transient lowElk are only an incidental presence here — a rare transient animal drifting through the river corridor or ag ground, reflected in a token harvest. Not a species to plan a hunt around in this unit.
- →Treat any elk as a chance encounter along the river bottoms or crop fields, not a target.
- →Focus effort on deer, which are the real opportunity in GMU 91.
Pro tips
- →This is a deer unit first — whitetail in the river bottoms, mule deer on the sage and ag edges.
- →Access is the limiter — most of the unit is private, so arrange permission, a trespass fee, or an outfitter early.
- →The small size and strong deer harvest reward a hunter who has locked down productive river-bottom ground.
- →Hunt the rut for the best whitetail action; it can run from late October into December on the plains.
- →State Trust sections are closed to hunting unless enrolled in CPW's Public Access Program.
Watch out for
- !Majority private with very limited public access — line up permission before the season.
- !State Trust sections are closed unless enrolled in CPW's Public Access Program.
- !The best whitetail river bottoms are tightly held private ground.
- !Section-line and private boundaries are easy to cross unintentionally — map carefully.
- !Dry, exposed prairie and fire risk during warm early seasons.
Logistics
Sterling is the regional service hub with full fuel, groceries, lodging, and gear, a short drive from this small unit. Interstate 76, US 138, and a grid of county roads reach the farm and river-bottom ground, but nearly all of it is private, so pre-arranged access and gate courtesy are essential. Cell coverage is generally decent across the ag country.
Nearest towns: Sterling, CO, Crook, CO, Iliff, CO, Fleming, 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 · HuntScore — GMU 91 (Logan County) · GoHunt — Colorado Unit Profiles
FAQ
- How big is GMU 91 in Colorado?
- GMU 91 (GMU 91 — Sedgwick Co.) covers about 77 square miles, ranging from roughly 3,600 to 4,300 feet in elevation. Area is computed from the unit boundary polygon.
- How much public land is in GMU 91?
- Approximately 5% of the unit is public land. Primary managers: private farm and ranch, CPW State Wildlife Areas (small parcels), State Trust Land (closed). Always verify ownership boundaries on the ground.
- What species does the catalog list for GMU 91?
- Whitetail Deer, Mule Deer, Rocky Mountain Elk. For seasons, tags, and regulations, use the official Colorado agency resources linked on this page — this page carries no regulatory information.
Put GMU 91 on your map.
Boundary lines, public/private ownership, topo, and offline maps for this unit — in Baseline Maps, free for 14 days.