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Keyhole State Park

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About Our Site - Keyhole State Park


Keyhole State Park offers swimming, hiking, boating, water skiing, bird-watching and fishing. Some of the state’s largest fish have been caught at Keyhole. You can also reserve one of our 3 group shelters to host weddings, family get togethers and company picnics. Keyhole State Park is located on the western edge of the Black Hills, between Sundance and Moorcroft, and is easily accessed off I-90 at exit 165. Travel north 6 miles and the entrance to Park Headquarters will be on your left. Keyhole State Park has 10 campgrounds, all of which are reservation only.




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Portion of Keyhole Reservoir Under HCBs Advisory


Advisory Regarding Harmful Cyanobacterial Blooms (HCBs) in Wyoming Waters

Keyhole Reservoir Under Advisory

The Wyoming Department of Health (WDH) is issuing an advisory for Keyhole Reservoir due to a harmful cyanobacterial bloom (HCB). This advisory is for the section of the reservoir near where Wind Creek intersects with Hwy. 113/Old Sundance Road only.

HCBs, previously referred to as harmful algal blooms or HABs, are associated with irritants and can produce a number of toxins that may pose a risk to people, pet and livestock health. In the event of an elevated risk or occurrence for toxin production by cyanobacteria, the WDH issues a recreational use health advisory. Under an advisory, WDH recommends the following:

  • Avoid contact with the water, especially in areas where cyanobacteria are dense and form scums. Do not use the water for recreational activities that involve frequent contact with the water (i.e., wading, skiing, bathing, and swimming).
  • The water should not be consumed. Boiling, filtration and/or chlorination will not remove cyanotoxins and will not make the water safe for drinking.
  • Fish can be eaten if they are rinsed with clean water. Eat only the fillet portion of the fish. Discard all fat, skin and organs before cooking as toxins are likely to collect in these tissues.
  • Avoid inhalation of water. Do not participate in recreational activities that may cause water to spray or mist. Boating is safe but avoid boating in areas with floating cyanobacteria scums.
  • Keep pets and/or livestock away from the water. Do not allow animals to drink the water, eat dried cyanobacteria, or groom themselves after contact with the water.

Contact with cyanobacteria can result in rashes, hives or skin blisters. Human consumption or inhalation of cyanotoxins can cause severe diarrhea, vomiting, nausea, numbness or dizziness. Signs of animal poisoning include weakness, staggering, difficulty breathing, convulsions and death. Cyanobacteria and toxins pose a special health risk for young children, pregnant women, people with compromised immune systems, pets and livestock. If people or animals come into contact with the water, rinse off with clean water as soon as possible. Seek medical attention or call Wyoming Poison Control Center at 1-800-222-1222 if you feel that you have been exposed to cyanotoxins and are experiencing adverse health effects. If pets or livestock are displaying symptoms, call a veterinarian.

Lakes or reservoirs under an Advisory are not closed. Marinas, lakeside parks and camping facilities are open for business. Any closed areas will be specifically noted. Visitors are advised to err on the side of caution, use their best judgement, and follow the recommendations by WDH when using the water.

The Wyoming Department of Environmental Quality (WDEQ), in cooperation with lake and reservoir management agencies, samples publicly accessible lakes and reservoirs in response to HCBs. Additional monitoring is being conducted on Keyhole Reservoir. WDH will let you know when the situation has been resolved or if additional precautions should be taken. WDH is working closely with Wyoming State Parks to minimize any potential harm.

For more information, please contact Dr. Karl Musgrave, State Environmental Health Epidemiologist, Wyoming Department of Health, at (307) 777-5825. An emergency hotline is available 24 hours a day at 1(888) 996-9104. Please share this information with all the other people who use the affected water, especially those who may not be aware of the advisory.



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Wyoming State Parks, Historic Sites & Trails
A Division of Wyoming State Parks & Cultural Resources
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Site Status


COVID-19 Coronavirus
Important Information:

Camping in Wyoming State Parks now open to ALL visitors. Reservations required. Social distancing guidelines in place. 



  • Our site is up and running year-round.
  • Our fee booths are open May thru October. When the booths are closed please use the fee canisters located at each entrance to pay fees.
  • Our office hours of operation are 7 a.m. to 3:30 p.m., Monday thru Friday.



Phone Number







 Keyhole State Park
 22 Marina Rd
 Moorcroft, WY 82721

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