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Animal Control

The Thornton Animal Control unit currently consists of four full-time officers who are available between the hours of 8 a.m. and 5 p.m., seven days a week, including all holidays. They handle primarily companion animal complaints and problems.

Below you will find some basic information on City ordinances pertaining to animals, and also a large section on wildlife that addresses some common issues. If you are having wildlife issues, we request that you read the information first and see if you can solve the problem with the information given. There is also contact information on other agencies and services relating to animals in the Denver Metro area. 

Animals Running at Large (Sec. 6-7): Your domestic animal (cats, dogs, etc.) must be confined to your property and not be allowed to wander off. When off your property, animals must be on a leash where you have effective and immediate control over them. Common areas are not considered owner's premises, and animals must be under control in common areas.

Never leave your animal in a public place unattended. 

Vaccination Required (Sec. 6-4): Every dog and cat over six months is required to be vaccinated for rabies and the tag must be attached to the pet's collar or harness.  

Quarantine Of Animals (Sec. 6-14): Any animal that bites a person must be reported to the police or animal control and be placed on quarantine for a period of 10 days. This can be done at the owners' residence or at a suitable shelter depending on the circumstances and at the discretion of the animal control officer.  

Aggressive Animals (Sec 6-17): Owners must prevent their animal from acting in an aggressive manner towards people or other animals. This could include a minor bite, chasing or lunging at a person, or leaning over a fence or wall while snarling or growling aggressively. 

Nuisances (Sec. 6-34):

  • Noise (Barking): Animals must not be allowed to bark unreasonably, excessively, continuously, or untimely. Don't allow your pet to become a nuisance by disturbing the neighborhood. If you are experiencing an animal that may be in violation of this ordinance, it is suggested that you attempt to communicate your concerns with the animal owner. If unsuccessful, suggestions and mediation are available through your Animal Control Officers.

  • Maintenance: Whether in public areas or at home, in areas where animals are kept the feces must be cleaned up and properly disposed of so as not to be a nuisance to others and to keep our city clean and sanitary.

  • Animal in Heat:  Female dogs and cats in heat must be securely confined to prevent unplanned breeding, and in such manner that the animal does not create a nuisance by attracting other dogs and cats.

Neglect of an Animal (Sec 6-28): All animals must be provided with sufficient food, water and shelter. Proper veterinary care is also required.  

Cruelty to Animals (Sec 6-31): All animals must be treated humanely, and not be placed into a situation that could potentially cause harm or suffering to them.

Reminder: Animals can quickly become overheated when left in parked cars on hot— or even warm – sunny days. Even with the windows slightly open, it takes just a short time before this type of heat can cause brain damage or death in an animal.

Animals Permitted (Sec 6-37): Each household may have up to a total of four adult animals, which can include dogs, cats and one Vietnamese potbellied pig. (Animals under three months old from the same litter are not included). Domestic birds, fish, snakes (under six feet) and reptiles that are nonpoisonous and not a health hazard are welcome.

Animals Prohibited (Sec 6-36): Livestock, rodents, fowl (except for two domestic ducks), exotic animals, wildlife, endangered animals, and poisonous species are not allowed.

Permits for Beekeeping(Sec 6-102): Permits for bee hives may be issued providing all applicable requirements are met, and a permit is obtained in accordance with the City's beekeeping regulations.

The City of Thornton, Colorado, offers a comprehensive list -- with phone numbers and addresses -- for local agencies in the Denver metro area that deal with animals and animal control issues.

Local Animal Control Agencies

Adams County... 720-523-6777

Arvada... 720-898-6850

Aurora... 303-326-8288

Boulder County Animal Control... 303-441-3626

City of Boulder Animal Control... 303-441-3333

Brighton... 303-655-2091

Broomfield... 303-438-6400

Commerce City... 303-288-1535

Denver Animal Protection... 303-698-0076

Federal Heights... 303-428-8539

Lakewood... 303-987-7173

Northglenn... 303-450-8886 or Dispatch... 303-288-1535

Westminster... 303-658-4326 or Dispatch... 303-658-4360


Area Animal Shelters

Adams County Animal Shelter

10705 Fulton Street, Commerce City... 303-288-3294

Aurora Animal Shelter

15750 E. 32nd Ave., Aurora... 303-326-8280

Humane Society of Boulder Valley

2323 55th St. Boulder... 303-442-4030

Brighton Animal Control


Denver Animal Shelter

1241 W. Bayaud Ave., Denver... 720-913-1311

Denver Dumb Friends League

2080 S. Quebec, Denver Main... 303-751-5772

Every Creature Counts

1245 Factory Circle, Ft. Lupton... 303-546-2704

Foothills Animal Shelter

580 McIntyre St., Golden... 303-278-7575

Longmont Humane Society

9595 Nelson Rd. #G, Longmont... 303-772-1232

MaxFund Shelter

1005 Galapagos St., Denver (dog)... 303-595-4917

720 W. 10th Ave, Denver (cat)….720-266-6081


State and Federal Agencies

Colorado Parks and Wildlife

6060 Broadway, Denver... 303-291-7227

Tri County Health Department

4301 E. 72nd Ave., Commerce City... 303-288-6816