Walleye Stocked · 16 plants · last June 16, 2026 Best: dawn, dusk, night Castle Rock Reservoir fishing
Castle Rock Reservoir fishing is stocked with Walleye, Smallmouth Bass, and Channel Catfish on a reservoir. Also recorded: Northern Pike, Largemouth Bass, Bluegill, Black Crappie, White Crappie, Pumpkinseed, and 1 more. It is stocked about 1.4 times a year since 2011, most often in June and August. Species guides list dawn, dusk, and night for Walleye and Black Crappie, dawn and dusk for Smallmouth Bass and Largemouth Bass, and dusk and night for Channel Catfish.
- Last stocked
- June 16, 2026
- · Walleye
- Plants on record
- 23
- Since 2011
- Species stocked
- 3 (+7 also recorded)
- Average size
- 1.7 in
- Elevation
- 3,259.3 ft
Fish at Castle Rock Reservoir
Around the dates Castle Rock Reservoir is stocked, Open-Meteo's 2016-2025 archive puts mean air temperature at 67.5°F in June, 73.4°F in August, 75.9°F in July, 64°F in September. That is air temperature at these coordinates, not water temperature. Open-Meteo
Walleye Stocked · 16 plants · last June 16, 2026 Best: dawn, dusk, night 
Channel Catfish Stocked · 5 plants · last September 30, 2021 Best: dusk, night Last stocked September 30, 2021 · avg 1.9 in · 5 plants
Best: dusk, night
Channel Catfish species guide
Smallmouth Bass Stocked · 2 plants · last August 3, 2018 Best: dawn, dusk 
Northern Pike Confirmed present Best: dawn, day, dusk Best: dawn, day, dusk
Northern Pike species guide
Largemouth Bass Confirmed present Best: dawn, dusk Best: dawn, dusk
Largemouth Bass species guide
Bluegill Confirmed present Best: dawn, day, dusk Best: dawn, day, dusk
Bluegill species guide
Black Crappie Confirmed present Best: dawn, dusk, night Best: dawn, dusk, night
Black Crappie species guide White Crappie Confirmed present
Pumpkinseed Confirmed present Best: dusk Best: dusk
Pumpkinseed species guide Green Sunfish Confirmed present
How Castle Rock Reservoir is stocked
Spotted Eagle Lake (50.9 mi) was stocked more recently. Spotted Eagle Lake is also stocked with Smallmouth Bass, Channel Catfish, and Walleye.
Fish stocked in 2011
1,000
Fish stocked in 2012
1,000
Fish stocked in 2013
1,000
Fish stocked in 2014
5,000
Fish stocked in 2015
2,000
Fish stocked in 2016
1,000
Fish stocked in 2017
2,000
Fish stocked in 2018
5,000
Fish stocked in 2019
1,000
Fish stocked in 2020
3,000
Fish stocked in 2021
10,227
Fish stocked in 2022
1,000
Fish stocked in 2023
1,000
Fish stocked in 2024
1,000
Fish stocked in 2025
1,000
Fish stocked in 2026
1,000
Stocking history
| Date | Species | Quantity | Avg. length | Source |
|---|---|---|---|---|
| June 16, 2026 | Walleye | 1,000 | 1.55 in | report |
| June 19, 2025 | Walleye | 1,000 | 1.29 in | report |
| June 11, 2024 | Walleye | 1,000 | 1.39 in | report |
| July 12, 2023 | Walleye | 1,000 | 2.01 in | report |
| June 15, 2022 | Walleye | 1,000 | 1.13 in | report |
| September 30, 2021 | Channel Catfish | 8,227 | 1.57 in | report |
| August 20, 2021 | Channel Catfish | 1,000 | 1.69 in | report |
| June 28, 2021 | Walleye | 1,000 | 1.76 in | report |
| August 19, 2020 | Channel Catfish | 1,000 | 1.61 in | report |
| June 10, 2020 | Walleye | 2,000 | 2.79 in | report |
| June 19, 2019 | Walleye | 1,000 | 1.59 in | report |
| August 3, 2018 | Smallmouth Bass | 4,000 | 2.19 in | report |
| June 24, 2018 | Walleye | 1,000 | 1.7 in | report |
| August 22, 2017 | Channel Catfish | 1,000 | 2 in | report |
| June 14, 2017 | Walleye | 1,000 | 1.51 in | report |
| June 14, 2016 | Walleye | 1,000 | 1.34 in | report |
| July 22, 2015 | Channel Catfish | 1,000 | 2.5 in | report |
| June 16, 2015 | Walleye | 1,000 | 2 in | report |
| September 2, 2014 | Smallmouth Bass | 4,000 | 2.49 in | report |
| June 24, 2014 | Walleye | 1,000 | 1.25 in | report |
| June 11, 2013 | Walleye | 1,000 | 1.5 in | report |
| June 11, 2012 | Walleye | 1,000 | 1.49 in | report |
| June 21, 2011 | Walleye | 1,000 | 1.12 in | report |
Access and facts
- Water type
- reservoir
- Nearest town
- Colstrip
- Facilities
- restrooms
Advisories, closures, regulations and water conditions change. Check the Montana Fish, Wildlife & Parks before you go.
Nearest lakes
Common questions
What fish are at Castle Rock Reservoir?
Fishing Castle Rock Reservoir usually means Walleye: Walleye accounts for 16 of 23 plants on record, ahead of Channel Catfish and one more. Walleye was last stocked June 16, 2026, averaging 1.6 in. Channel Catfish was last stocked September 30, 2021, averaging 1.9 in. Smallmouth Bass was last stocked August 3, 2018, averaging 2.3 in. Northern Pike, Largemouth Bass, Bluegill, and Black Crappie, plus 3 more are recorded here outside the stocking reports.
When is Castle Rock Reservoir stocked?
Last stocked June 16, 2026. It is stocked about 1.4 times a year since 2011, most often in June and August.
How big are the fish stocked at Castle Rock Reservoir?
Stocked fish average 1.7 in. Walleye average 1.6 in. Channel Catfish average 1.9 in. Smallmouth Bass average 2.3 in.
How do you get on Castle Rock Reservoir?
The nearest town is Colstrip. Facilities include restrooms.
Which lakes near Castle Rock Reservoir were stocked more recently?
Spotted Eagle Lake (50.9 mi) was stocked more recently. Spotted Eagle Lake is also stocked with Smallmouth Bass, Channel Catfish, and Walleye.