Aug 10, 2026

Horsetooth Reservoir and Horsetooth Mountain With a Dog: 7 Access Points Ranked

Horsetooth is seven access points with seven sets of rules, two leash limits, and one exclusion that catches people on the hottest day of the year.

Luis ZamoraCo-founder of PetCompass; Dog Dad to Banzo and Tuck

Fort Collins, Colorado10 min readThings to Do

Horsetooth is the reason people move to Fort Collins. Six and a half miles of water at 5,420 feet, wrapped in 1,900 acres of public land, with a 2,711-acre mountain open space rising behind it to 7,255 feet and carrying 29 miles of trail.

It is also, for a dog, seven different places with seven different rules, two different leash limits, and one hard exclusion that catches people out on the hottest day of the year.

The Larimer County leash limit is ten feet, which is a full four feet more generous than the City of Fort Collins natural areas and Rocky Mountain National Park. But the county is stricter in a way that matters more: its regulations state that physical control specifically does not mean eye or voice command, or electronic devices. A perfectly trained dog off leash is a violation here. An e-collar is not a substitute.

Ranked below by what your dog actually gets.

1. Horsetooth Mountain Open Space, main trailhead

County Road 38E, north side of the road, about 2.5 miles west of the South Bay entrance. Entrance permit required. Open year round. Main trailhead closed 11 p.m. to 4 a.m.

The best dog hiking within fifteen minutes of Fort Collins. The open space covers 2,711 acres across the former Culver, Soderberg, and Hughey Open Spaces, from 5,430 feet up to 7,255, with 29 miles of hiking, biking, and horseback trails.

Horsetooth Rock is the landmark, visible from the plains, and Horsetooth Falls runs in spring. The trail network connects onward to the Blue Sky Trail and into Lory State Park, so the mileage available is far greater than the open space boundary suggests.

Drinking water is available at the trailhead, which the county flags while telling you to carry enough for the whole hike anyway. Do that. This is dry, exposed, south-facing ground for much of its length.

Four miles from Fort Collins and twelve miles northwest of Loveland.

2. Lory State Park

708 Lodgepole Drive, Bellvue. Open daily 5 a.m. to sunset. Daily vehicle pass $10 to $15, individual daily pass $4. Telephone 970-493-1623.

The quieter way into the same hills. Lory's trails connect directly to the Horsetooth Mountain network, so you can reach the same country from the north side with fewer people at the trailhead.

Colorado Parks and Wildlife permits leashed dogs, requiring them to be leashed and under control at all times. The park also adds, fairly, that for the best wildlife viewing you should leave pets at home.

The 5 a.m. opening is the selling point in a Colorado summer, and the sunset closing is the limitation. No evening walks here.

3. Soderberg Trailhead

Shoreline Drive, 1.2 miles from the Horsetooth Reservoir Inlet Bay entrance. Open sunrise to sunset.

The second door into Horsetooth Mountain, and the one to use when the main trailhead car park is full, which on a summer weekend it will be.

Note the different hours. Soderberg is sunrise to sunset while the main trailhead runs to 11 p.m. If you are planning a late finish, start from the main lot instead.

4. Devil's Backbone Open Space

West of Loveland. 3,007 acres, 17.25 miles of trail.

A hogback rather than a mountain, and one of the most visible geologic landmarks in Larimer County, with red-tailed hawks, grassland wildflowers, and towering rock outcrops.

Its trails connect to Horsetooth Mountain Open Space, which makes it part of the same system rather than a separate trip.

One warning that matters. Those trails also connect to Rimrock Open Space, and dogs are not allowed at Rim Rock Open Space under Larimer County regulations. Know where that boundary is before you let the miles carry you into it.

Check the trailhead water status. The county posts closures for repairs to the fountain and spigot, so carry your own.

5. Inlet Bay

Continue west on County Road 38E about 1.75 miles past the South Bay entrance, then turn right on Shoreline Drive.

Marina and campground, and the access point that puts you closest to Soderberg. Reservoir shoreline rather than trail, so treat it as a water and camping base rather than a walk.

Entrance and camping permits are required, and the reservoir is open year round.

6. Lions Open Space and the Pleasant Valley Trail

Just south of Laporte on North Overland Trail. No entrance fee. Open year round, sunrise to sunset.

Not Horsetooth, and on the list because it is free. Lions sits on the banks of the Cache la Poudre River with day-use picnicking, fishing, hiking, and biking, and holds the westernmost portion of the Poudre River Trail, which continues west as the paved Pleasant Valley Trail to Watson Lake in Bellvue.

Three-acre Bingham Hill Park sits at the top of Bingham Hill on County Road 50E, with shelters, picnic tables, and a view over Pleasant Valley and Bellvue.

Why it is here rather than higher. It is flat, paved, riverside, and free, which makes it the right answer for an older dog, a hot afternoon, or a day when you do not want to pay for a permit. More Poudre options are in the Poudre is Colorado's only Wild and Scenic river.

7. South Bay

South end of the reservoir on County Road 38E. Campground, Group Pavilion, and swim beach.

Last, and for one specific reason. Larimer County regulations prohibit knowingly or negligently allowing dogs or other animals to enter the swimming areas, land or water, and the county's own summary is blunt about why: no pets on swim beaches, because waste contaminates the water.

So the most obvious place to cool a dog down is the one place you cannot. On a hot day, with a dog in the car and a beach in front of you, that is the single most common mistake made at Horsetooth.

South Bay is still useful. It holds the Horsetooth Area Information Center, staffed on 970-498-5610, open 9 a.m. to 4 p.m. seven days a week from March to October and Monday to Friday from November to February with a lunch closure from 12:30 to 1:00. Start there for permits and current conditions.

The seven at a glance

Rank	Access point	Dogs	Hours	Fee
1	Horsetooth Mountain, main trailhead	Leashed, 10 ft	Closed 11 p.m. to 4 a.m.	Permit
2	Lory State Park	Leashed	5 a.m. to sunset	$4 to $15
3	Soderberg Trailhead	Leashed, 10 ft	Sunrise to sunset	Permit
4	Devil's Backbone	Leashed, 10 ft	Year round	Permit
5	Inlet Bay	Leashed, 10 ft	Year round	Permit
6	Lions Open Space	Leashed, 10 ft	Sunrise to sunset	Free
7	South Bay	No dogs on the swim beach	Year round	Permit

The Larimer County dog rules in full

These apply across the whole county open space system, and they are more specific than most.

Physical control is required, and it is defined. The regulations state that physical control specifically does not mean eye or voice command or electronic devices. Where a leash is used, it may not exceed ten feet.

Three county properties ban dogs outright. The regulations prohibit allowing a dog or other animal at Prairie Ridge Natural Area, Rim Rock Open Space, or Red Mountain Open Space. Add those to the seven city natural areas listed in the 7 natural areas where Fort Collins bans dogs and you have ten sites in the region that will turn you away.

No dogs in swimming areas, land or water.

Harassing wildlife is a violation whether or not the animal is injured, and it applies knowingly or negligently.

Aggressive dogs are excluded by notice. Once a Larimer County Ranger has deemed a dog aggressive or vicious, it may not remain in or return to the system, and the rule applies to whoever brought the dog rather than only the registered owner. The same applies to any dog that has bitten, scratched, pulled down, or injured a person or another domestic animal.

Service animals are welcome at all properties, leashed, with waste picked up.

Cooling a dog down without the swim beach

Since the obvious answer is off the table, it is worth knowing the ones that are not, because Horsetooth in July is genuinely hot and the trails are exposed.

Go at 4 a.m. rather than solving it later. The main Horsetooth Mountain trailhead opens at four precisely because summer here has a usable window and an unusable one. A dog walked from four to seven does not need cooling down.

Use the shaded north-facing draws. Horsetooth Mountain spans 1,800 feet of elevation, and the gullies on the shaded side hold cool air and damp ground long after the open slopes have baked. Horsetooth Falls in spring is the obvious example.

Carry more water than the dog will drink and use the surplus. Wetting the groin, armpits, and paw pads cools far more effectively than pouring water over a thick coat, which can trap heat against the skin.

Drop to the river instead of the reservoir. Lions Open Space sits on the Cache la Poudre with genuine river access and no entrance fee, which makes it the sensible swap on a hot afternoon.

And read the ground before you commit. Exposed rock and hardpacked trail on a south-facing Front Range slope gets hot enough to injure pads, and the check takes seven seconds with the back of your hand.

Practical planning

Get the permit before you arrive. Both Horsetooth Reservoir and Horsetooth Mountain Open Space require entrance permits, and the reservoir also requires camping permits.

Start early. Horsetooth Mountain is exposed, south-facing, and hot by mid-morning in summer. The main trailhead's 4 a.m. opening is not decorative.

Carry all the water. There is drinking water at the Horsetooth Mountain trailhead and the county still tells you to carry enough for the whole outing.

Watch for fire restrictions, which the county posts prominently and which change through the season.

Know the hazards. Rattlesnakes on the hogbacks, foxtails in dry grass, blue-green algae in still water, and afternoon storms on exposed ridges are all covered in 9 Colorado hazards that catch Fort Collins dog owners off guard.

And if the dog needs off-leash time, none of these places is it. The four fenced options are ranked in 4 Fort Collins off-leash dog parks.

Frequently asked questions

Are dogs allowed at Horsetooth Mountain Open Space? Yes, under physical control. Larimer County requires a leash no longer than ten feet, and states that physical control specifically does not mean eye or voice command or electronic devices.

Can my dog swim at Horsetooth Reservoir? Not at the swim beach. Larimer County regulations prohibit allowing dogs into swimming areas, land or water, because waste contaminates the water.

What is the leash length at Horsetooth? Ten feet, under Larimer County Department of Natural Resources regulations. That is longer than the six-foot limit in Fort Collins city natural areas and Rocky Mountain National Park.

Do I need a permit for Horsetooth with a dog? You need an entrance permit for both Horsetooth Reservoir and Horsetooth Mountain Open Space. There is no separate dog permit.

How big is Horsetooth Mountain Open Space? 2,711 acres, spanning elevations from 5,430 to 7,255 feet, with 29 miles of trail connecting onward to the Blue Sky Trail and Lory State Park.

Which Larimer County open spaces ban dogs? Prairie Ridge Natural Area, Rim Rock Open Space, and Red Mountain Open Space.

Sources

Permits, fees, hours, trailhead closures, water availability, and fire restrictions change through the season. Confirm with Larimer County before travelling. This article is general information and is not veterinary advice.