Fishing the Afterbay

Beautiful sunset on the Afterbay
A beautiful sun rises in the east on the Afterbay

NPS (Henthorne)


As the Yellowtail Dam generates power, the water is collected in the Afterbay reservoir. The intent is to preserve a constant flow of the Bighorn River for fish and wildlife habitat.
The Afterbay is 181 acres in size and is often used by anglers for shoreline and motor boat fishing. Please read the following information to help you have an enjoyable experience on the Afterbay.

Fishing: The Afterbay’s main species is rainbow trout. Brown trout, carp, ling and other warm water species can also be found in the reservoir. The Afterbay is stocked by Montana Fish, Wildlife and Parks every third year. The next stocking will occur in spring 2010 with 6” to 8” rainbow trout. Some of the best places to shoreline fish include: the buoy line at the Afterbay Dam, close to the campgrounds, and around the Historic Big Horn Headgate. Keep in mind:

  • Bait fishing is allowed
  • Bow fishing is allowed outside of campgrounds
  • No warm water stamp is required
  • Fish limits: 5 trout combined (no size limit)

Note: This page does not provide all the fishing regulations. To see the fishing regulations for Montana click here...

Boating: There is a boat launch on the south side of the Afterbay. Motor boating is allowed on the reservoir with the exception of the area closest to Yellowtail Dam (beyond the orange log boom near the historic Bighorn Head Gate). Restricted areas are also identified and delineated by signs or boat restraining systems.

Caution: Keep in mind that the water in the Afterbay can fluctuate up to 15 feet. Instances have occurred where boats have been beached and overturned due to daily fluctuations.

Camping: There are two campgrounds at the Afterbay, one on the south side with 24 spaces and another on the north side with 12 spaces. There is also hard sided camping only in the parking lot of the Afterbay Boat launch.

Swimming: Do not swim in the Afterbay! Though the reservoir does not freeze, the water temperature rarely gets warmer then the mid-40s, even wading in these waters can be treacherous.

Last updated: October 25, 2012

Contact the Park

Mailing Address:

Bighorn Canyon National Recreation Area Headquarters Office
PO Box 7458

Fort Smith, MT 59035


(307) 548-5406

Contact Us