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Rating depth structure for rainbow trout.
Shared by DepthScout anglers. Exact spots stay private, always.
372-acre reservoir near Fremont. The lake tops out around 26 ft. The chart is a model: real shoreline, published maximum depth, interpolated in between. A planning tool, never a navigation product. Here's the year, species by species, as the scoring engine sees it.
Drawn out, this is 280 acres of water rimmed by 11.2 miles of bank. The 4.8 development index tells the story — a convoluted bank whose fishable edge far outruns the acreage. Littoral water — the productive band under ~15 ft — makes up 90% of this chart, as modeled. Call it 3.3 mi long by 1.5 mi wide at the broadest reach. You'll find it in Fremont County. The nearest mapped water is Henrys Fork, 12 mi to the northeast.
When the water first warms, cutthroat trout slide up into 3 to 15 ft. By summer they slide out to 7 to 26 ft, and by winter most fish are in 7 to 26 ft. If you only fish one area, make it Main-lake point: a point around 8 ft that scores prime in fall. In summer the feeding windows fall in early morning and the evening. Keep a trolled spoon (small) or an inline spinner rigged through the warm months.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 15 ft | dawn & dusk | Main-lake point (8 ft) | Inline spinner (silver/gold), Small spoon |
| Summer | 7 to 26 ft | dawn & dusk | Main-lake point (8 ft) | Trolled spoon (small), Inline spinner |
| Fall | 5 to 25 ft | dawn & dusk | Main-lake point (8 ft) | Casting spoon, Inline spinner |
| Winter | 7 to 26 ft | dawn | Deep basin (22 ft) | Small jigging spoon, Marabou jig |
In spring, rainbow trout run shallow here, mostly 5 to 20 ft. Summer pushes them deeper, 7 to 26 ft, and winter fish settle into 5 to 26 ft. Main-lake point is the standout, a point at roughly 8 ft, rated prime for spring rainbow trout. Time it for early morning and the evening. You won't need more than a dodger + spoon (deep troll) or a flutter spoon most summer days.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 5 to 20 ft | dawn & dusk | Main-lake point (8 ft) | Inline spinner (silver), Small spoon |
| Summer | 7 to 26 ft | dawn & dusk | Main-lake point (8 ft) | Dodger + spoon (deep troll), Flutter spoon |
| Fall | 7 to 26 ft | dawn & dusk | Main-lake point (8 ft) | Casting spoon, Jerkbait over shoals |
| Winter | 5 to 26 ft | dawn | Deep basin (22 ft) | Jigging spoon, Tube jig (white) |
The chart marks 5 structure features on Ashton Reservoir; the deepest is Deep basin at about 22 ft.
| Date | Species | Count | Size |
|---|---|---|---|
| Apr 2 | Rainbow Trout | — | ~13" |
| Apr 1 | Rainbow Trout | — | ~13" |
Source: Idaho Fish & Game stocking records, retrieved 2026-09-03.
Season dates, license requirements, and size and bag limits for Idaho waters are set by the Idaho Fish and Game — and special regulations can apply to Ashton Reservoir specifically, so confirm the current rules before you fish.
Check the official Idaho fishing regulations →
Ashton Reservoir is about 26 ft (8 m) deep at its deepest point. The contours here are modeled from the water's real shape and maximum depth, so treat them as a rough guide.
Anglers target cutthroat trout, rainbow trout on Ashton Reservoir.
Main-lake point is the top-rated area: a point in about 8 ft of water that rates prime for cutthroat trout in fall. Every other rated spot, per species and season, is on the map above.
For cutthroat trout, the summer bite is best in early morning and the evening. Each species page section below lists the seasonal windows, and the map shows a live NOW badge when you're inside one.
Yes — per Idaho Fish & Game stocking records records, Ashton Reservoir was most recently stocked Apr 2 with rainbow trout. The full stocking history is listed above.
Fishing on Ashton Reservoir is regulated by the Idaho Fish and Game. Check the official Idaho regulations for current license requirements, season dates, and size and bag limits — special regulations can apply to this specific water.
Henrys Fork 12 mi · Fish Lake 27 mi, WY · Tillery Lake 32 mi, WY · Grassy Lake Reservoir 33 mi, WY · Henrys Lake 37 mi · Red Rock Lake, Upper 38 mi, MT · Lake Solitude 38 mi, WY · Widgeon Pond 39 mi, MT · Holly Lake 40 mi, WY · Elk Lake (Beaverhead) 41 mi, MT · Bearpaw Lake 41 mi, WY · Jackson Lake 42 mi, WY
See how Ashton Reservoir stacks up: best rainbow trout lakes in Idaho · best cutthroat trout lakes in Idaho
Browse all Idaho fishing maps or see every water on DepthScout. How we build these maps. Fish here with a sonar unit that logs? Send us your depth data and we'll improve this chart, credited to you. For fishing guidance only, never navigation.