GMU 103 GMU 103 — Yuma Co.
Small plains deer unit with a rare slice of public access at South Republican
Far southeast Yuma County — South Fork Republican River near the Kansas line · Last reviewed 2026-07-12
Area
129
sq mi
Public land
8%
approx.
Elevation
3,600–4,100
feet
Motorized
moderate
access
Overview
GMU 103 is a compact unit tucked into far southeastern Yuma County against the Kansas border, drained by the South Fork of the Republican River. It's a deer-first unit — whitetails in the wooded river bottoms and mule deer on the surrounding sandsage and farm breaks — with only incidental elk. Unlike its neighbors, GMU 103 contains the South Republican State Wildlife Area around the old Bonny Reservoir bed, giving it a genuine (if limited) block of walk-in public hunting amid otherwise private farm and ranch ground.
Terrain
Low rolling plains draining into the South Fork Republican River valley; the broad former Bonny Reservoir basin adds bottomland cover and edge habitat.
Cover: Cottonwood/willow river bottoms and shelterbelts, sandsage and shortgrass prairie, dryland and irrigated crops, and grassland/wetland flats in the old reservoir bed.
Landmarks: South Fork Republican River · South Republican State Wildlife Area (former Bonny Reservoir) · Idalia · Kansas state line
Access
Mostly private, but the South Republican State Wildlife Area provides a real block of public walk-in hunting along the river corridor — the standout access feature of this unit. State Wildlife Area regulations (and any daily-pass/hunting-license requirements) apply. Colorado State Trust Lands remain closed to public hunting unless enrolled in CPW's Public Access Program. Beyond the SWA, expect to need landowner permission or a Walk-In Access lease.
Managers: private farm, private ranch, CPW State Wildlife Area (South Republican), Colorado State Trust Land (access-restricted)
Access points: South Republican State Wildlife Area parking and river-corridor access · County road grid off US 385 near Idalia · CPW Walk-In Access parcels (annual atlas)
Species notes
Whitetail Deer
common qualityWhitetails are the signature deer of the South Fork Republican bottoms — cottonwoods, brush, and the old reservoir edge hold good numbers. Limited-draw, with the SWA offering rare public whitetail ground.
- →Hunt river-bottom cottonwoods and brush edges in the SWA
- →Set on travel between bedding cover and crop fields
- →Rut hunts along the river corridor are the highlight
Mule Deer
common qualityMule deer use the sandsage breaks, grass draws, and crop edges away from the river, overlapping whitetails at the field margins. Fully limited-draw.
- →Glass draws and CRP edges at first/last light
- →Pattern movement between grass bedding and crops
- →Work the transition between open breaks and river cover
Rocky Mountain Elk
transient lowElk are essentially absent as a resident resource — only rare plains wanderers, with negligible harvest.
- →Not a target species; treat any elk as purely opportunistic
Pro tips
- →Scout and hunt the South Republican SWA river corridor for public-land whitetails
- →Time later hunts to the whitetail rut in the bottoms
- →For private ground beyond the SWA, secure permission or a Walk-In lease early
- →Confirm current SWA rules and any pass/license requirements before hunting there
Watch out for
- !Outside the SWA the unit is almost entirely private — know your boundaries
- !State Trust Lands are closed unless enrolled in the Public Access Program
- !The Kansas state line runs the east edge — do not cross while hunting
- !River-bottom roads and the old reservoir flats get muddy and impassable when wet
Logistics
Idalia is the nearest small town; Wray to the north and Burlington to the south (I-70) offer fuel, lodging, and groceries. The road grid is graded 2WD-friendly county roads that slick up when wet. Cell coverage is spotty in the river bottoms.
Nearest towns: Idalia, Wray, Burlington, St. Francis, KS
Seasons & regulations
This page carries no season dates or regulations. Get current rules from the official Colorado sources:
Research sources: Colorado Parks & Wildlife — GMU boundary descriptions · CPW Big Game Harvest Statistics
FAQ
- How big is GMU 103 in Colorado?
- GMU 103 (GMU 103 — Yuma Co.) covers about 129 square miles, ranging from roughly 3,600 to 4,100 feet in elevation. Area is computed from the unit boundary polygon.
- How much public land is in GMU 103?
- Approximately 8% of the unit is public land. Primary managers: private farm, private ranch, CPW State Wildlife Area (South Republican), Colorado State Trust Land (access-restricted). Always verify ownership boundaries on the ground.
- What species does the catalog list for GMU 103?
- 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 103 on your map.
Boundary lines, public/private ownership, topo, and offline maps for this unit — in Baseline Maps, free for 14 days.