Sep 3, 2026

Where Dogs Are Not Allowed in Boulder

A city that opens 155 miles of trail to dogs needs exclusions, and Boulder publishes them trail by trail. The full list, plus the behaviour that is prohibited everywhere.

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

Boulder, Colorado8 min readPet Care & Services

Boulder has more places dogs cannot go than any city in this series, and that is a direct consequence of how much ground it opens to them. A system with 155 miles of trail and a licensed off-leash programme needs exclusions, and Boulder publishes them trail by trail.

Here is the complete picture across two separate systems, with the rule behind each and the source that publishes it.

City open space: trails closed to dogs year-round

From the city's trail regulations table, rows labelled No Dogs for the whole trail:


Boy Scout	East Boulder - Teller Lake #5
Goshawk Ridge	Greenbriar Connector
Hogback Ridge	Lion's Lair
Lion's Lair Spur	Long Canyon
May's Point	McClintock Upper
Sombrero Marsh	Spring Brook Loop South
Towhee

And part-trail bans, which are the ones you walk into by accident:

Trail	Where dogs are banned, as published
E.M. Greenman	"No Dogs from Saddle Rock to Green Mountain West Ridge"
East Boulder - White Rocks	"No Dogs north of Valmont Road"
McClintock Lower	"No Dogs on southern segment"
South Boulder Creek	"No Dogs south of Cherryvale"
North Sky	"Grassland Bird, No Dogs May 1 to July 31"

North Sky is the seasonal one. Dogs are barred for three months and allowed on lead the rest of the year. Our dogs on OSMP trails guide covers the four regimes and the counting caveat, since rows in the city's table can carry more than one rule.

City open space: where off leash is not allowed

Three overlapping restrictions, and none of them is optional if you hold a Voice and Sight tag.

Every leash-required trail. Verbatim from the Voice and Sight page: "All trails posted as requiring a leash prohibit the use of voice and sight control." Seventy-six rows in the trail table carry that label.

Every trailhead. Verbatim from Dogs on OSMP: "The Trailhead Leash Program requires dog guardians to leash their dogs upon exiting their vehicle at all OSMP trailheads, and in the area of the trailheads."

And more than 20 feet from the trail on eight named trails, under the On-Corridor Voice and Sight regime, verbatim: "dogs are allowed no more than 20 feet away from the trail."

Plus the whole city outside designated areas. Verbatim: "On-leash control is always required within the city limits of Boulder except in specially designated dog parks or other areas specifically exempted from this requirement."

City open space: the seasonal windows

Two of them, verbatim: "Seasonal Leash restrictions are in place May 1 - July 31 & Aug. 15 - Dec. 1 on some trails to protect ground-nesting birds and bears."

Bear season affects four named areas: portions of Gregory Canyon, Saddle Rock, Amphitheater and Bluebell-Baird Trails, Skunk Canyon up to the Mesa Trail, Shadow Canyon South from the Mesa Trail to the intersection with Shadow Canyon North, and the upper part of Doudy Draw above Springbrook Loop.

And the end date is disputed on the city's own site, with the trail table saying November 1 and both the news release and the OSMP dogs page saying December 1. Our seasonal dog leash restrictions guide sets out both.

Boulder County open space: four properties, no dogs at all

A separate system with separate rules. Verbatim from Boulder County: "These properties are considered prime wildlife habitat areas and dogs are not allowed at" Caribou Ranch, Dodd Reservoir, Hall Ranch and Heil Valley Ranch.

Hall Ranch and Heil Valley Ranch have a documented history, verbatim: "The decision to ban dogs from Hall Ranch and Heil Valley Ranch was made in 2006 after seven years of studies, dog-leash compliance monitoring, and many public meetings."

Everything else on county land is leash-required except two properties, and one of those two also appears on the leash-required list. Our dogs on Boulder County open space guide covers the full lists and that conflict.

A city Voice and Sight tag is worthless out there. The county runs no equivalent programme.

City parks: on lead, and banned at sports complexes

Verbatim from the dog parks page: "Dogs are allowed on leash in most Boulder parks. Areas where dogs are not allowed, such as sports complexes, have signs posted."

"Such as sports complexes" is the city's only worked example, and the signage is the operative rule.

Even inside a dog park, the rules bite on the approach. Verbatim: "Leash laws do apply to all areas as you approach or exit the dog parks, whether walking home or to your parked vehicle."

And in the off-leash areas themselves, verbatim: "Aggressive animals are prohibited and should not be brought to dog parks." Our Boulder dog parks guide covers the four sites, including Howard Heuston, where off leash applies only "north of the partial fence" and "Leashes are required in the remainder of the park."

Behaviour that is prohibited anywhere

Not places, but they end an outing just as fast.

Chasing wildlife or livestock. Verbatim from Dogs on OSMP: "it is illegal for you and your dog to chase or disturb wildlife or livestock." And on one species in particular, verbatim: "it's against the law to do so and you could face a hefty fine! Keep your dog away from prairie dogs on prairie dog colonies!"

Leaving waste, even bagged. Verbatim: "It is required by law that you immediately dispose of pet waste by either putting it in the nearest dog waste bin or taking it with you." And from a city article on the subject, verbatim: "Leaving dog waste bags on a trail or in a park is considered littering".

Tying a dog up while you climb. Verbatim: "When rock climbing or bouldering, make sure you or someone in your party is with your dog. It is illegal to leave your dog tied up while you enjoy your climb."

And off-leash walking without a tag, which the city treats as an infraction in its own right alongside walking more than two dogs off lead and failing to carry a leash for each. Our Voice and Sight Tag Program guide covers the whole list and the penalty ladder, which runs from a maximum $100 first violation to not less than $300 for a third within 24 months, with possible permanent revocation of privileges.

Why there are so many exclusions here

Worth answering, because a list this long can read as a hostile city and Boulder is the opposite.

The exclusions are the price of the access. A system that lets registered dogs run off lead across a large share of 155 trail miles has to protect the places where that does not work: ground-nesting bird habitat, bear foraging corridors, marshes, restoration areas and a handful of narrow summit trails where a loose dog and a descending hiker cannot pass safely.

Compare the alternative. Most cities in this series solve the same problem by making everything leash-only and fencing off a few acres for off-leash play. Boulder has four fenced sites and an entire trail network instead, and the cost is a map you have to read.

The county's four closures make the same trade differently. Verbatim from Boulder County: "These properties are considered prime wildlife habitat areas and dogs are not allowed at" the four named. Two of those followed seven years of study and compliance monitoring, which is the county saying it tried leashes first.

The practical conclusion for a dog owner is not "Boulder restricts dogs". It is that Boulder expects you to check before each walk, in exchange for access most Front Range cities do not offer. Our dogs on OSMP trails guide is the reference for that check, and the city's interactive dog regulations map is the version that updates in real time.

The short version

Thirteen city trails are closed to dogs outright, plus five with part-trail or seasonal bans.

Four county properties are closed to dogs entirely, two of them after a seven-year study.

Everywhere in the city outside a designated dog park or an off-leash trail is lead-only, including every trailhead and the walk to and from your car.

Two seasonal windows suspend off-leash access on named trails, for birds in early summer and bears from mid-August.

If you are new here, our moving to Boulder with a dog guide sequences the first month, and our Boulder dog licence guide covers the thirty-day deadline that starts the day you arrive.

Frequently asked questions

Which Boulder trails are closed to dogs? The city's trail table lists Boy Scout, East Boulder Teller Lake #5, Goshawk Ridge, Greenbriar Connector, Hogback Ridge, Lion's Lair, Lion's Lair Spur, Long Canyon, May's Point, McClintock Upper, Sombrero Marsh, Spring Brook Loop South and Towhee as No Dogs, plus part-trail bans on E.M. Greenman, East Boulder White Rocks, McClintock Lower and South Boulder Creek.

Which Boulder County properties ban dogs? Caribou Ranch, Dodd Reservoir, Hall Ranch and Heil Valley Ranch, which the county describes as prime wildlife habitat areas.

Is any trail closed to dogs only part of the year? Yes. North Sky is listed as No Dogs from May 1 to July 31 under the grassland bird restriction.

Do I need a lead at the trailhead? Yes. The Trailhead Leash Program requires dogs to be leashed on exiting your vehicle at all OSMP trailheads and in the area of the trailheads.

Can I use voice and sight control on a leash-required trail? No. The city states that all trails posted as requiring a leash prohibit the use of voice and sight control.

How far can my dog go from the trail on an On-Corridor trail? No more than 20 feet, and you must stay on the trail yourself.

Sources

Trail lists and closures change, and the underlying code could not be read at source. Check the city's table, its interactive map and the signage on site.