Island Park Reservoir Fishing
A 7,280-acre Idaho reservoir in Fremont County.
Pick for kokaneePiscifun Carbon X ultralight spinning reel28% OFFSale $57.99 Photo of Teton River: Waldemarpaetz Troutster.com, CC BY 3.0
An opening look at Island Park Reservoir
Spread over 7,280 acres, Island Park Reservoir sits in Fremont County by the Planner figure. Expect about 6,302 feet of elevation at the water, per USGS mapping. Regional biologists of the IDFG Upper Snake Region oversee it. St. Anthony, some 31 miles distant, is the nearest town. IDFG location note: Flows into the Henrys Fork Snake River. IDFG tags it a Recommended Fishing Water.
Boaters can pick from 9 launch sites in the IDFG, BLM and Forest Service data. 651 stocking records appear on its Planner page, the oldest from 1968. The facility line reads: boat ramp, dock, toilet and accessible facilities.
Surface acres as listed in the IDFG Idaho Fishing Planner (water page), read November 7, 2026. Elevation from the USGS National Hydrography Dataset and GNIS for the matched lake outline, read November 7, 2026. Census 2020 places.
Game fish IDFG recommends at Island Park Reservoir
Fish tied to Island Park Reservoir in IDFG data, recommended game fish first:
IDFG sampling results for Island Park Reservoir
- Brook Troutsurvey 2009
- Cutthroat Troutsurvey 2009
- Kokaneesurvey 2009
- Largescale Suckersurvey 2009
- Rainbow Troutsurvey 2009
- Utah Chubsurvey 2009
- Utah Suckersurvey 2009
- Mountain Whitefishsurvey 2008
Not every surveyed fish is a game fish.
IDFG Idaho Fishing Planner water page, read November 7, 2026.
For the kokanee herePiscifun Carbon XT ultralight spinning reel25% OFFSale $59.99 Getting a boat wet on Island Park Reservoir
- Box Canyon Boating Ramp on Island Park Reservoirboating – motorized, ramp, USDA Forest Service
- Box Canyon boat ramp on Island Park Reservoirfishing access, ramp, restroom
- Buttermilk Boat Ramp on Island Park Reservoir (south)boating – motorized, ramp, USDA Forest Service
- Buttermilk boat ramp on Island Park Reservoir (north)boating access, ramp, restroom, camping
- Island Park Boating Site boat rampboating – motorized, ramp, USDA Forest Service
- Island Park boat rampboating access, ramp, dock, restroom
- West End boat ramp on Island Park Reservoirboating access, ramp, dock, restroom, camping
- Island Park Reservoir boat rampboating – motorized, ramp, USDA Forest Service
- West End Boat Ramp on Island Park Reservoirboating – motorized, ramp, USDA Forest Service
Launch sites a short haul from Island Park Reservoir
- Mill Creek boat rampMill Creek, 7 miles northeast
- Last Chance boat rampfishing access, restroom, 7 miles east
- McCrea Bridge Boat Rampboating – motorized, ramp, 8 miles northeast
- McCrea boat rampboating access, ramp, restroom, camping, 8 miles northeast
- Riverside boat rampfishing access, ramp, restroom, camping, 10 miles southeast
- Sand Creek Ponds boat rampSand Creek, 13 miles south
Walk-in fishing access near Island Park Reservoir
- Buffalo ADA fishing accessfishing access, restroom, camping, 9 miles
The Planner lists no motor restriction here.
IDFG Fishing and Boating Access Sites layer, BLM Idaho recreation site points and USDA Forest Service recreation opportunities (EDW), read November 7, 2026.
How full Island Park Reservoir sits
| USGS gauge | Latest reading | Time (ET) |
|---|---|---|
| Island Park Dam Nr Island Park Id | 148.23 ft gage height | Nov 9 7:45 pm |
US Geological Survey provisional data, retrieved Nov 9, 2026 8:33 pm ET. Provisional readings can be revised.
USGS lake gauges refresh live; Corps figures are the dated reading we pulled.
Hatchery fish added to Island Park Reservoir
IDFG lists 651 releases into Island Park Reservoir (1968 to 2026); recent ones follow.
- Rainbow Trout (triploid)Rainbow Trout – Triploid, 10,514 fish, Catchable (12-14 inches), October 22, 2026
- Rainbow TroutRainbow Trout, 18,720 fish, Catchable (12-14 inches), May 20, 2026
- Rainbow Trout (triploid)Rainbow Trout – Triploid, 5,363 fish, Catchable (12-14 inches), September 30, 2025
- Rainbow Trout (triploid)Rainbow Trout – Triploid, 5,148 fish, Catchable (12-14 inches), September 26, 2025
- Rainbow Trout (triploid)Rainbow Trout – Triploid, 10,605 fish, Catchable (12-14 inches), June 18, 2025
- Rainbow Trout (triploid)Rainbow Trout – Triploid, 7,968 fish, Catchable (12-14 inches), May 13, 2025
- Rainbow Trout (triploid)Rainbow Trout – Triploid, 13,270 fish, Catchable (12-14 inches), October 2, 2024
- Rainbow Trout (triploid)Rainbow Trout – Triploid, 9,180 fish, Catchable (12-14 inches), June 24, 2024
- Rainbow Trout (triploid)Rainbow Trout – Triploid, 3,600 fish, Catchable (12-14 inches), June 18, 2024
- Rainbow Trout (triploid)Rainbow Trout – Triploid, 9,632 fish, Catchable (12-14 inches), May 30, 2024
Stocking rows as printed on the IDFG Fishing Planner page (date, species, number and size as listed), read November 7, 2026.
Keeping fish at Island Park Reservoir
| Group | Region rule as printed |
|---|---|
| Bass | Bass – no bag, length, or possession limits |
| 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 15 |
| 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 | Trout limit is 6, all species combined; Bull Trout and Brook Trout are listed separately |
| Walleye | No bag, length, or possession limits, harvest is encouraged (Have not been stocked intentionally in this Region. May be harmful to existing fisheries.) |
| Whitefish | Whitefish limit is 25 – see Big Lost River exception; 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 including Bluehead Sucker | May not be harvested or possessed (also known as Green Sucker) |
| All Other Fish Species | No bag, length or possession limit |
Island Park Reservoir follows the IDFG Upper Snake Region limits unless its own rules say otherwise.
Fishing here takes an Idaho fishing license; Idaho Code 36-416 sets the annual statutory fee at $28.75 for residents and $106.25 for nonresidents, and steelhead or salmon fishing takes its own permit.
Region bag limits from Idaho Fishing Seasons and Rules, 2025-2027 for the Upper Snake Region, as printed on IDFG Fishing Planner water pages (the brochure PDF on idfg.idaho.gov was unreachable during site maintenance), read November 7, 2026.
Fishing license fees as set in Idaho Code 36-416 (statute; IDFG sale prices add vendor and processing fees), read November 7, 2026.
Island Park Reservoir next to nearby lakes
Silver Lake leads this group on size, 165 acres by the Planner.
| Lake | Distance | Acres | Region | Recommended fish | Launch sites |
|---|---|---|---|---|---|
| Island Park Reservoir | 7,280 | Upper Snake Region | 2 | 9 | |
| Trudes Reservoir | 1 mile north | 89 | Upper Snake Region | 0 | 0 |
| Silver Lake | 5 miles southeast | 165 | Upper Snake Region | 0 | 0 |
| East Harriman Fish Pond | 8 miles southeast | 31 | Upper Snake Region | 1 | 0 |
| Blue Creek Reservoir (Fremont County) | 12 miles south | 8.4 | Upper Snake Region | 2 | 0 |
| Upper Arcadia Reservoir | 17 miles south | 35 | Upper Snake Region | 0 | 0 |
IDFG Idaho Fishing Planner and the agency access layers, read November 7, 2026.
A short hop from Island Park Reservoir
More Idaho lakes and reservoirs around Island Park Reservoir
- Trudes Reservoir1 mile north
- Silver Lake5 miles southeast
- East Harriman Fish Pond8 miles southeast
- Blue Creek Reservoir (Fremont County)12 miles south
- Upper Arcadia Reservoir17 miles south
Stores to hit before Island Park Reservoir
- Henry's Fork Anglersbait and tackle shop, Island Park, 7 miles
- TRR – Henry's Fork Shuttle Servicebait and tackle shop, Ashton, 26 miles
- House of Harropbait and tackle shop, Saint Anthony
- Idaho Irresistiblesbait and tackle shop, Ashton
- Three Rivers Ranch Outfittersbait and tackle shop, Ashton
Hiring an outfitter for Island Park Reservoir
- TroutHunterfly shop and guide service, Island Park
Towns a reasonable drive from Island Park Reservoir
- St. Anthony31 miles
- Sugar City38 miles
- Rexburg42 miles
County guides that cover Island Park Reservoir
- Fremont Countyseat: Saint Anthony
Piscifun tackle lined up for a day on Island Park Reservoir
Piscifun and Amazon links are affiliate links; the site earns a commission on qualifying purchases.
Benchland and bank around Island Park Reservoir, seen through a lens
Photo: Ken Lund, CC BY-SA 2.0
Photo: Ken Lund, CC BY-SA 2.0
Photo: BLMIdaho, CC BY 2.0
Photo: Doug Kerr, CC BY-SA 2.0
Loose ends to tie up before Island Park Reservoir
Which county lines cross Island Park Reservoir?
Head for Fremont County, about 31 miles from St. Anthony.
How many acres is Island Park Reservoir?
Roughly 7,280 acres, at about 6,302 feet.
Where do I launch a trailered boat at Island Park Reservoir?
9 launch sites, including Box Canyon Boating Ramp on Island Park Reservoir.
Which game fish does IDFG recommend at Island Park Reservoir?
IDFG points anglers to kokanee and rainbow trout.
Is there a size limit on fish kept at Island Park Reservoir?
Under the IDFG Upper Snake Region block: Trout limit is 6, all species combined; Bull Trout and Brook Trout are listed separately. Kokanee: Kokanee limit is 15.
Where do I buy a license before Island Park Reservoir?
Fishing here takes an Idaho fishing license; Idaho Code 36-416 sets the annual statutory fee at $28.75 for residents and $106.25 for nonresidents, and steelhead or salmon fishing takes its own permit.
How often is Island Park Reservoir stocked?
The Planner lists 651 rows, latest Rainbow Trout – Triploid, 10,514 fish, Catchable (12-14 inches), October 22, 2026.
Which tackle counter on our Idaho list serves Island Park Reservoir?
Closest on our list: Henry's Fork Anglers, about 7 miles away.
Is Island Park Reservoir sitting high or drawn low at the moment?
The level band draws on USGS.
Gas up and head for Island Park Reservoir
Buy the Idaho license before the drive.