Grassy Lake Reservoir

Grassy Lake Reservoir fishing

Fishing at Grassy Lake Reservoir is on a reservoir, stocked with Cutthroat Trout, Rainbow Trout, and Lake Trout. It is stocked about once a year since 1997, most often in June and July. Species guides list dawn and dusk for Rainbow Trout and dawn for Lake Trout.

Last stocked

June 1, 2026

Plants on record

29

Since 1997

Species recorded

1

Average size

5.8 in

Elevation

7,201 ft

Access and facts

Water type
reservoir

Bureau of Reclamation reservoir on Ashton-Flagg Ranch Road between Yellowstone and Grand Teton, reached via Forest Service Road 135 east of US-89/287. Recreation.gov notes no improvements, services, or facilities on site; primitive access only.

Sources: water_type , shore_notes , speciesFound , fishing_notes , watch_outs

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How Grassy Lake Reservoir is stocked

The first plant of the year usually falls in the first week of July. In 2026 it was June 1, 2026, earlier than usual.

No plants recorded in 1999 and 2000.

Fish Lake (6.4 mi) was stocked more recently. Fish Lake is also stocked with Cutthroat Trout.

Fish at Grassy Lake Reservoir

Fishing Grassy Lake Reservoir is most likely to be for Cutthroat Trout. All 29 plants on record are Cutthroat Trout.

Cutthroat Trout 29 plants
Plants
29 of 29
Last stocked
June 1, 2026
Average length
5.8 in

Seasons and rigs are on the Cutthroat Trout guide.

Fishing Grassy Lake Reservoir

Grassy Lake Reservoir, a 1,477-acre reservoir, is located near the Wyoming-Idaho border between Yellowstone and Grand Teton National Parks. Popular activities at Grassy Lake include fishing. Anglers can find fish species such as rainbow, cutthroat, and lake trout in this reservoir.

Sources: recreation.gov

What to watch for

There are no improvements, services, or facilities at Grassy Lake.

Fish stocked per year

  • 15,7461997
  • 16,8031998
  • 16,5342001
  • 16,1792002
  • 14,8082003
  • 15,6522004
  • 15,1842005
  • 15,1682006
  • 15,2282007
  • 14,4062008
  • 17,3252009
  • 5,2292010
  • 12,2762011
  • 7,8752012
  • 14,9942013
  • 11,9162014
  • 13,5002015
  • 15,2652016
  • 16,0922017
  • 16,3422018
  • 14,4482019
  • 15,0172020
  • 15,8722021
  • 15,0202022
  • 16,2962023
  • 16,4952024
  • 16,0542025
  • 15,0092026

Stocking history

Showing 15 of 29 plants Showing 29 plants

Source: Wyoming Game and Fish Department.
Date Species Quantity Avg. length Source
June 1, 2026 Cutthroat Trout 15,009 5.2 in report
June 1, 2025 Cutthroat Trout 16,054 5.5 in report
June 1, 2024 Cutthroat Trout 16,495 5.5 in report
July 1, 2023 Cutthroat Trout 16,296 5.8 in report
July 1, 2022 Cutthroat Trout 15,020 5.2 in report
July 1, 2021 Cutthroat Trout 15,872 5.6 in report
July 1, 2020 Cutthroat Trout 15,017 5.9 in report
July 1, 2019 Cutthroat Trout 14,448 5.1 in report
July 1, 2018 Cutthroat Trout 16,342 5.2 in report
July 1, 2017 Cutthroat Trout 16,092 4.7 in report
July 1, 2016 Cutthroat Trout 15,265 5.1 in report
June 1, 2015 Cutthroat Trout 13,500 4.6 in report
July 1, 2014 Cutthroat Trout 4,356 4.3 in report
June 1, 2014 Cutthroat Trout 7,560 4.3 in report
July 1, 2013 Cutthroat Trout 14,994 5.4 in report
July 1, 2012 Cutthroat Trout 7,875 5.5 in report
July 1, 2011 Cutthroat Trout 12,276 7.4 in report
July 1, 2010 Cutthroat Trout 5,229 6.8 in report
July 1, 2009 Cutthroat Trout 17,325 6.4 in report
August 1, 2008 Cutthroat Trout 14,406 7 in report
June 1, 2007 Cutthroat Trout 15,228 6.8 in report
July 1, 2006 Cutthroat Trout 15,168 6.4 in report
July 1, 2005 Cutthroat Trout 15,184 5.6 in report
July 1, 2004 Cutthroat Trout 15,652 7.4 in report
July 1, 2003 Cutthroat Trout 14,808 6.1 in report
July 1, 2002 Cutthroat Trout 16,179 7.1 in report
June 1, 2001 Cutthroat Trout 16,534 7.4 in report
July 1, 1998 Cutthroat Trout 16,803 5.4 in report
August 1, 1997 Cutthroat Trout 15,746 6.4 in report
Show 14 more plants Show less

Species found here

Confirmed present independent of the stocking records above, not from a stocking event.

  • Rainbow trout : Listed by Recreation.gov as a fish species present at Grassy Lake Reservoir; not part of this lake's tracked stocking history. (source)
  • Lake trout : Listed by Recreation.gov as a fish species present at Grassy Lake Reservoir; not part of this lake's tracked stocking history. (source)

Species stocked here

Depth-by-season, top lures, and bait notes for each species stocked here are on its own species guide, linked above.

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