Campground dog rules in Colorado, by who runs the land
Almost every Colorado campground allows dogs. The differences are the leash rule, which trails you can walk from your site and what happens at the water, and all three depend on the land manager.
Colorado State Parks (CPW). Parks regulation 2 CCR 405-1 #100.C.16 requires pets under control and on a leash no longer than six feet except when confined in a vehicle or boat. E-collars and dragging leashes do not count; rangers can cite or evict. Parks add their own limits: at Cheyenne Mountain State Park near Colorado Springs, dogs may use campsites but only a few named trails, and not the cabins. Our state parks guide goes park by park.
US Forest Service. In developed campgrounds, 36 CFR 261.16(j) requires animals crated, caged or on a leash no longer than six feet. Outside developed sites there is no blanket federal leash rule; each forest sets it by order, and voice control is allowed across much of the White River and San Juan national forests. Wilderness tightens it again: Indian Peaks and James Peak require a hand-held leash, and Maroon Bells-Snowmass requires leashes and bars dogs from the Conundrum Hot Springs permit zone. See dispersed camping with dogs.
Reservoirs and national parks. Horsetooth Reservoir near Fort Collins allows a 10-foot leash and bans dogs from the swim beaches, as most Front Range reservoirs do. Rocky Mountain National Park allows no dogs on any trail.
Two things apply everywhere: fire restrictions are set by county and by forest, change weekly in summer and are posted at the entrance, and most campgrounds prohibit leaving a dog unattended at the site. Where a campground's own pages post no pet rule, as at Heaton Bay near Frisco, the card tells you to confirm on recreation.gov.