Grasmere Reservoir

Snake River Drainage

  • Recommended Fishing Water

Grasmere Reservoir in Owyhee County is 224.5 acres.

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Grasmere Reservoir is a remote irrigation reservoir with slightly turbid water throughout most of the year. Lahontan cutthroat are the primary game fish. Crayfish are abundant also.

Facilities

Motor Restriction
No
Boat Ramp
No
Dock
No
Toilet
Yes
Campground
No
ADA Access
Yes

Recommended Game Fish

Species Observed in Surveys

Fish Stocking Records

Date
Species
Quantity
General Size
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Date
Species
Quantity
General Size
2024/10/04 Cutthroat Trout - Lahontan 19,936 Fingerling (3-6 inches)
2023/10/06 Cutthroat Trout - Lahontan 20,040 Fingerling (3-6 inches)
2022/09/26 Cutthroat Trout - Lahontan 20,036 Fingerling (3-6 inches)
2021/09/28 Cutthroat Trout - Lahontan 26,112 Fingerling (3-6 inches)
2020/09/29 Cutthroat Trout - Lahontan 28,240 Fingerling (3-6 inches)
2019/09/11 Cutthroat Trout - Lahontan 30,984 Fry (0-3 inches)
2018/09/25 Cutthroat Trout - Lahontan 25,734 Fingerling (3-6 inches)
2017/09/21 Cutthroat Trout - Lahontan 23,276 Fingerling (3-6 inches)
2016/09/29 Rainbow Trout - Triploid 1,036 Catchable (6+ inches)
2013/09/23 Cutthroat Trout - Lahontan 29,827 Fingerling (3-6 inches)
2012/09/19 Cutthroat Trout - Lahontan 33,880 Fingerling (3-6 inches)
2010/09/22 Cutthroat Trout - Lahontan 24,898 Fingerling (3-6 inches)
2009/09/08 Cutthroat Trout - Lahontan 20,280 Fry (0-3 inches)
2008/06/25 Cutthroat Trout - Lahontan 49,236 Fry (0-3 inches)
2007/06/28 Cutthroat Trout - Lahontan 49,918 Fry (0-3 inches)
2006/06/13 Cutthroat Trout - Lahontan 20,868 Fry (0-3 inches)
2005/06/16 Cutthroat Trout - Lahontan 20,944 Fry (0-3 inches)
2004/06/16 Cutthroat Trout - Lahontan 28,000 Fry (0-3 inches)
2003/06/24 Cutthroat Trout - Lahontan 24,840 Fry (0-3 inches)
2002/06/25 Cutthroat Trout - Lahontan 24,600 Fry (0-3 inches)
2001/06/21 Cutthroat Trout - Lahontan 24,641 Fry (0-3 inches)
2000/06/13 Cutthroat Trout - Lahontan 25,185 Fry (0-3 inches)
1998/06/24 Cutthroat Trout - Lahontan 24,900 Fry (0-3 inches)
1997/06/19 Cutthroat Trout - Lahontan 15,460 Fry (0-3 inches)
1996/06/18 Cutthroat Trout - Lahontan 7,490 Fry (0-3 inches)
1995/06/27 Cutthroat Trout - Lahontan 7,475 Fry (0-3 inches)
1994/06/08 Cutthroat Trout - Lahontan 6,000 Fry (0-3 inches)
1993/06/29 Cutthroat Trout - Lahontan 13,075 Fry (0-3 inches)
1992/10/27 Cutthroat Trout - Lahontan 2,700 Fingerling (3-6 inches)
1991/11/19 Cutthroat Trout - Lahontan 3,120 Fingerling (3-6 inches)
1988/09/10 Cutthroat Trout - Lahontan 10,250 Fingerling (3-6 inches)
1986/04/17 Rainbow Trout 6,080 Catchable (6+ inches)
1985/05/21 Rainbow Trout 6,080 Catchable (6+ inches)
1983/05/26 Rainbow Trout 6,120 Catchable (6+ inches)
1982/05/28 Rainbow Trout 8,510 Catchable (6+ inches)
1981/03/25 Rainbow Trout 2,700 Catchable (6+ inches)
1980/04/30 Rainbow Trout 7,440 Catchable (6+ inches)
1979/06/29 Rainbow Trout 1,410 Catchable (6+ inches)
1979/05/03 Rainbow Trout 5,760 Catchable (6+ inches)
1978/05/19 Rainbow Trout 7,200 Catchable (6+ inches)
1976/06/01 Rainbow Trout 6,300 Catchable (6+ inches)
1976/05/21 Rainbow Trout 5,040 Catchable (6+ inches)
1975/06/25 Rainbow Trout 3,960 Catchable (6+ inches)
1975/05/28 Rainbow Trout 5,520 Catchable (6+ inches)
1974/05/22 Rainbow Trout 6,510 Catchable (6+ inches)
1973/04/06 Rainbow Trout 6,090 Catchable (6+ inches)
1973/03/19 Rainbow Trout 4,320 Catchable (6+ inches)
1972/03/16 Rainbow Trout 3,360 Adults
1972/03/15 Rainbow Trout 3,360 Adults
1971/05/12 Rainbow Trout 7,920 Catchable (6+ inches)
1971/04/29 Rainbow Trout 7,200 Catchable (6+ inches)
1971/04/14 Rainbow Trout 3,600 Catchable (6+ inches)
1970/07/08 Rainbow Trout 14,310 Fry (0-3 inches)
1970/06/11 Rainbow Trout 14,700 Catchable (6+ inches)
1969/05/16 Rainbow Trout 23,340 Fry (0-3 inches)
1969/05/14 Rainbow Trout 5,250 Catchable (6+ inches)
1969/05/05 Rainbow Trout 5,460 Catchable (6+ inches)
1968/05/24 Rainbow Trout 4,080 Catchable (6+ inches)
Source: IDFG Fish Stocking Database.

Licenses and Tags

Learn more about IDFG Licenses, Tags & Permits
 

Be aware of Fish Consumption Advisories associated with this waterbody. More information can be found here.

Fishing Rules, 2025 - 2027

All Waters Open All Year

Except as modified in Special Rules
Fishing is not allowed within the posted upstream and downstream boundary of any fish weir or trap.

Daily Bag Limits

The following daily bag limits apply to all waters within each region except as modified in the Special Rules. The possession limit is 3-times the daily bag limit.

Special Rules

No Special Rules for Grasmere Reservoir.
Southwest Region Bag Limits
Bass (Largemouth and Smallmouth)

  • Bass limit is 6, both species combined
  • None under 12 inches

Brook Trout

  • Brook Trout limit is 25
  • Harvest allowed during any open season unless otherwise noted under Special Rules - if gear or bait restrictions are listed, they apply when fishing for Brook Trout

Bull Trout

  • Bull Trout - catch-and-release

Kokanee

  • Kokanee limit is 6

Salmon (ocean-run)

  • Spring and summer Chinook Salmon seasons and limits are set by the Idaho Fish and Game Commission and issued in separate brochures
  • Seasons and limits for fall Chinook Salmon and Coho Salmon can be found here
  • Sockeye Salmon fishing is illegal. Defined as ocean-run Oncorhynchus nerka longer than 14 inches in the Snake River drainage below Hells Canyon Dam, the Salmon River drainage (excluding above Mosquito Flat Dam)
  • Fishing for salmon is prohibited unless a salmon season is specifically opened for that water

Steelhead (ocean-run)

  • Defined as Rainbow Trout longer than 20 inches in the Salmon River drainage (excluding lakes and reservoirs). Between Hells Canyon Dam and Oxbow Dam and the Boise River from its mouth upstream to Barber Dam during steelhead seasons, steelhead are Rainbow Trout over 20 inches with the adipose fin clipped (as evidenced by a healed scar)
  • Fishing for steelhead is prohibited unless a steelhead season is specifically opened for that water. See fishing regulations for details

Sturgeon

  • Sturgeon - catch-and-release
  • Sturgeon must not be removed from the water and must be released upon landing
  • Barbless hooks, sliding swivel device to secure a weight, and a lighter test line to secure weight to sliding swivel device are required. See fishing regulations for details

Tiger Muskie

  • Tiger Muskie limit is 2, none under 40 inches

Trout includes Brown Trout, Lake Trout, Golden Trout, Arctic Grayling, Cutthroat Trout, Rainbow Trout, land-locked Chinook and Coho Salmon, trout hybrids (e.g. Tiger Trout)

  • Trout limit is 6, all species combined
  • Chinook Salmon and steelhead placed in ponds are counted in the trout bag limit
  • Bull Trout and Brook Trout are listed separately

Walleye (Stocked illegally in this Region. May be harmful to existing fisheries.)

  • No bag, length, or possession limits. Harvest is encouraged

Whitefish

  • Whitefish limit is 25
  • Harvest allowed during any open season unless otherwise noted under Special Rules - if gear or bait restrictions are listed, they apply when fishing for whitefish

Protected Nongame Fish includes Pacific Lamprey

  • May not be harvested or possessed

All Other Fish Species includes bullfrogs and crayfish

  • No bag, length, or possession limits
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