Cooney Reservoir

Boat Ramps: 3
Access Points: 3
Species: 3

Cooney Reservoir is a popular fishing destination located in south-central Montana, approximately one hour southwest of Billings and near the communities of Roberts, Joliet, Boyd, and Red Lodge. Originally constructed in 1937 as an irrigation reservoir, Cooney spans approximately 733 acres with a maximum depth of 97 feet when at full pool. The reservoir sits at an elevation of 4,244 feet and offers spectacular views of the Beartooth Mountains. Cooney is known for its excellent fishing opportunities for several species, particularly rainbow trout and walleye, making it one of the most visited water-based recreation areas in Montana. As part of Cooney State Park, the reservoir provides various amenities for anglers including boat ramps, campgrounds, and shoreline access.

Montana licenses and regulations4 to check before you go

Species & education

Learn what type of fish are at Cooney Reservoir and what's needed to catch them.

Find which waters have the species you want to catch

Rainbow Trout

Oncorhynchus mykiss

Walleye

Sander vitreus

Burbot

Lota lota

Fish stocking schedule

Latest 5 stockings

Rainbow Trout5,181 fish · 9.0 inMay 21, 2026
Rainbow Trout7,850 fish · 9.0 inMay 20, 2026
Rainbow Trout9,959 fish · 2.4 inMar 9, 2026
Rainbow Trout5,525 fish · 9.7 inOct 16, 2025
Rainbow Trout4,410 fish · 11.6 inOct 14, 2025

Source

Montana Fish, Wildlife & Parks

Updated Nov 13, 2026. Sizes are the length the agency reports. Dates are as precise as the agency reports them.

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Fishing spots, boat ramps & amenities

Learn how to get on Cooney Reservoir. Uncover great fishing access points, boat ramps, and all the facilities you need for an unforgettable day on the water. Some locations shown may border or include private property. Always check property boundaries and applicable regulations before visiting. onWater's Public & Private Land layer can help you plan your access with confidence.

Know where you can legally fish on Cooney Reservoir

See public and private land boundaries along the water, turn on private parcels with owner details to know where permission is required, and find land-trust parcels that offer permitted fishing access.

Montana licenses and regulations

Montana Boating Regulations

When using any type of watercraft to access a body of water, it is important to follow all federal, state, and local rules and regulations. These rules and regulations include boat permitting and licensing, invasive species inspections and stamps, life jacket and PFD rules, motor size and horsepower restrictions, noise limitations, restrictions on personal watercraft, and many more. Visit the web link below for the most current rules and regulations for this body of water.

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Montana Fishing License

All anglers 12 and over must possess a license.

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Montana Fishing Regulations

This river has a variety of species and regulations, including potential floating and/or watercraft restrictions. Because this river is specially managed for species, seasons, angling methods, and watercraft, it is strongly encouraged you check all federal, state, and local regulations before fishing. Visit any of the links below, inquire locally, or contact a local fly shop to learn current regulations and restrictions.

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Montana Stream Access Laws

Under the Montana Stream Access Law, the public may use rivers and streams for recreational purposes up to the ordinary high water marks. Although the law gives recreationists the right to use rivers and streams for water-related recreation, it does not give them the right to enter private lands bordering those streams or to cross private lands to gain access to streams without landowner permission. Montana's stream access law ensures public access to surface waters by public bridge or county road right-of-way. The width of a public bridge or public road right-of-way easement is the same as the public highway to which it is attached.

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Take Cooney Reservoir with you

The onWater Fish app keeps this water's access points, species and conditions in your pocket, with the tools you use once you're there.

Use the map without signal
Download the map around Cooney Reservoir to use it offline when coverage drops.
Log your catches here
Keep a private fishing journal for Cooney Reservoir to find where and when fish are biting for you.
HD depth charts from Garmin
Find drop offs, ledges, channels, points and shallow flats with Garmin depth charts in the app.