Sep 3, 2026

Dogs on Boulder's OSMP Trails: Four Regimes, Trail by Trail

Four rules, 155 miles of trail, and a table where the regime can change at a landmark or on a Saturday. What applies where, and the 20-foot limit most tag holders have never read.

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

Boulder, Colorado11 min readThings to Do

Boulder's open space does not have a dog rule. It has four, and which one applies depends on the trail, the season, and on two trails the day of the week.

The regimes, as the city labels them in its own trail regulations table:

Leash Required
Leash, Or Voice and Sight Control
On-Corridor Voice and Sight
No Dogs

Most trails are the second. The fourth exists on more trails than people expect. And the third has a distance limit most tag holders have never read.

The scale you are dealing with

Verbatim from the Dogs on OSMP page: "OSMP lands have approximately 155 miles of trails and 89 percent of them are open to dogs on leash."

Eighty-nine percent on leash. Which means roughly one trail mile in nine is closed to dogs entirely, and the off-leash subset is smaller again.

The city's framing of the whole system, verbatim: "Open Space and Mountain Parks is one of few systems on the Colorado Front Range which allow dog guardians to walk dogs off-leash."

Regime 1: Leash Required

The default on the busiest and most sensitive trails. In the table as we read it, 76 rows carry "Leash Required", including trails such as the 6th through 9th Street Connectors, Bear Canyon, Bear Peak West Ridge, Coalton, Cottontail, Cowdrey Draw and the Devils Thumb Access.

A leash-required trail cannot be walked under voice and sight control, whatever tag your dog wears. Verbatim from the Voice and Sight page: "All trails posted as requiring a leash prohibit the use of voice and sight control."

Regime 2: Leash, Or Voice and Sight Control

The most common label, appearing in 105 rows in the table. On these trails a registered dog wearing a Voice and Sight tag may be off lead, and any other dog must be on one.

Our Voice and Sight Tag Program guide covers what registration involves, including the control standard the city defines and the two-dog limit.

Regime 3: On-Corridor Voice and Sight, the 20-foot rule

Eight rows in the table carry this label: Anemone Loop, Bear Peak, Green Mountain Summit, Joder Ranch, Ranger, Reflection Point, South Boulder Peak and Vesper.

What it means, verbatim from the Voice and Sight page:

"Some trails require that visitors stay on the trail and also allow dogs to be managed under voice and sight control. The purpose for requiring people to stay on trail is to limit impacts to the area where the trail is located in sensitive resource and restoration areas. On trails where dog guardians are required to stay on trail and dogs can be managed under voice and sight control, dogs are allowed no more than 20 feet away from the trail."

Twenty feet, and you stay on the trail. So a dog casting into the meadow to investigate something is out of compliance on these eight even though it is off lead legally.

Vesper also carries a seasonal overlay, verbatim: "On-Corridor Voice and Sight. Grassland Bird, Leash Required May 1 to July 31".

Regime 4: No Dogs

Worth memorising, because arriving at a trailhead with a dog in the car is a wasted trip.

Whole trails listed as No Dogs in the table as we read it: 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.

Part-trail bans, which are easier to walk into by accident:

Trail	Where dogs are banned
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, Leash Required on northern segments"
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.

One counting note, stated plainly: rows in the city's table often carry more than one regime, so the numbers above are row counts rather than trail totals. Check the city's table or its interactive dog regulations map for the trail you are actually walking.

The rules that split by landmark, and two that split by day

This is the part that catches visitors. Many Boulder trails change regime partway along.

Baseline, verbatim: "Leash Required for all dogs east of 6th Street Connector. Leash, Or Voice and Sight Control to the west of 6th Street Connector."

Chautauqua, verbatim: "Leash Required east of 6th Street Connector. Leash, Or Voice and Sight Control west of 6th Street Connector."

Chapman Drive, verbatim: "East of Tenderfoot Leash, Or Voice and Sight Control. West of Tenderfoot Leash Required."

Bluebell Road, verbatim: "Leash Required on northern Portion of Trail. Leash, Or Voice and Sight Control south of Chautauqua Park neighborhood."

Cherryvale, verbatim: "Leash Required east of South Boulder Creek. Leash, Or Voice and Sight Control west of South Boulder Creek."

And a day-of-week rule. Big Bluestem West, verbatim: "Leash Required Sat & Sun. Leash, Or Voice and Sight Control Mon - Fri."

A weekday habit that works on Big Bluestem West is a violation on Saturday. That is the single best argument for reading signage even on a trail you know.

The trailhead rule, which applies everywhere

Before any of the above matters, there is one rule at every car park. Verbatim from the Dogs on OSMP page:

"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."

Leash on before the door shuts, at every trailhead, whatever the trail's regime. The city's reason, verbatim: "Trailheads are busy places with cars and people coming and going."

The seasonal overlays

Two windows sit on top of everything above. 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."

May 1 to July 31 is ground-nesting birds. August 15 onward is bear foraging season, and the end date is one the city's own pages disagree about. Our Boulder's seasonal dog leash restrictions guide sets out both dates and the named trails, and our dogs and wildlife in Boulder guide covers the animals behind the rules.

Waste is a legal duty here, not an etiquette point

The number the city publishes is the reason. Verbatim: "Did you know that an estimated 80,000 pounds of pet waste are left behind on OSMP property every year?"

The rule, 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."

"Immediately", and there is no leave-it-and-collect-it option. The city addresses that plan directly, verbatim: "Thinking "I'll pick it up on my way back?"" And from a March 2026 city article on the same subject, verbatim: "Leaving dog waste bags on a trail or in a park is considered littering, so carrying it to the trash can is an important part of the process."

A composting programme exists at named trailheads, verbatim: "OSMP is participating in a dog waste composting program at several trailheads and access points." The list includes Dry Creek, Bobolink, Mount Sanitas, Eagle, South Teller, Marshall Mesa, South Mesa, Sawhill Ponds, Wonderland Lake, Boulder Valley Ranch and Cottonwood among others.

And the city's own summary line, verbatim: "Remember, there is no "poop fairy.""

Multi-use means more than dogs

Verbatim: "Most trails on OSMP are multi-use, meaning that they are open to bikes, horses, dogs, hikers and runners."

The table confirms it per trail, with separate columns for bikes, e-bikes and horses. A dog off lead on a multi-use trail is sharing space with cyclists at speed and horses that spook, which is the practical reason the city's control standard demands compliance "without regard to circumstances or distractions".

The city's expectation, verbatim: "Remember that to avoid a sticky situation, you and your dog must not be aggressive toward other people or dogs, and it is illegal for you and your dog to chase or disturb wildlife or livestock."

The other rules that ride along with a trail walk

Three from the city's own dogs page, all of which apply on any regime.

Ice. Verbatim: "You can help to keep you and your pets safe by keeping them off OSMP's icy lakes." And if it goes wrong, verbatim: "If it happens to you while visiting OSMP and your pet is unable to get out of the water, stay off the ice! Call 911 and Boulder Fire-Rescue will respond and rescue your pet!"

Climbing. 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." Illegal, not discouraged. In a city where the trail and the crag are often the same trip, that is worth knowing.

Prairie dogs. 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!" The city does not state the amount, so we are not printing one.

And on heat, the city's own signs list, verbatim: "Excessive panting" / "Lying down often/unwilling or unable to get up" / "Dark red gums/later pale gums" / "Dry mucous membranes and/or thick saliva" / "Disoriented or unstable". Our summer heat safety for pets guide covers the physiology, and our pet first aid basics guide covers the response. Boulder's own first aid instruction is more specific than most, and our emergency vets in Boulder guide has the 24-hour hospitals for when it is past first aid.

A practical routine for a Boulder trail walk

Check the regime before you drive. The table and the interactive map are both linked from the Dogs on OSMP page, and the regime can change halfway along the trail.

Leash on at the car, under the Trailhead Leash Program.

Carry a leash per dog, and no more than two dogs off lead if you are using voice and sight.

Assume 20 feet on the eight On-Corridor trails, and stay on the path yourself.

Carry the waste out. Immediately, and no staging it beside the trail.

Leash up around wildlife regardless of your tag. The city's own advice, verbatim: "Not sure what your dog will do when encountering wildlife on Open Space? Play it on the safe side and leash your pup until you or the wildlife has passed."

If your dog is not ready for any of this, the fenced dog parks are where the city says to train, and our Boulder dog parks guide covers them. For the wider picture of restrictions, see where dogs are not allowed in Boulder, and for the county's separate rules see dogs on Boulder County open space.

Frequently asked questions

How many dog regimes does Boulder's open space use? Four, as labelled in the city's trail regulations table: Leash Required, Leash Or Voice and Sight Control, On-Corridor Voice and Sight, and No Dogs.

How much of OSMP is open to dogs? The city states that OSMP lands have approximately 155 miles of trails and 89 percent of them are open to dogs on leash.

What is On-Corridor Voice and Sight? A regime on eight trail rows where visitors must stay on the trail and dogs may be under voice and sight control but are allowed no more than 20 feet away from the trail.

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

Do I need a leash at the trailhead even on an off-leash trail? Yes. The Trailhead Leash Program requires guardians to leash dogs on exiting their vehicle at all OSMP trailheads and in the area of the trailheads.

Can a trail change its dog rule partway along? Yes, and many do. Baseline, Chautauqua, Chapman Drive, Bluebell Road and Cherryvale all switch regime at a named landmark.

Sources

Trail regimes and seasonal overlays change. Check the city's table, its interactive map and the signage at the trailhead before you go.