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515-acre reservoir in Box Elder County, Utah. The lake tops out around 20 ft. This chart interpolates between a real shoreline and a known maximum depth. It will point you at likely water, but it is not a navigation product. What the data behind the map says about each species, season by season:
Mantua Reservoir maps at 503 acres behind 4.1 miles of shoreline. Nearly circular (index 1.3), so the story is the bottom, not the bank. The shallow band under 15 ft claims about 77% of the surface on the model — that's where the groceries are. Tip to tip the water measures near 1.1 mi with a 1.1-mi widest point. Box Elder County claims this one. Its nearest charted neighbour, Hyrum Reservoir, is 9 mi to the northeast.
When the water first warms, bluegill slide up into 1 to 6 ft. Summer is a 4 to 15 ft game here, winter a 6 to 20 ft one. Start at Shallow bay flat. It's a weed flat holding about 3 ft of water and rates prime come spring. The feeding windows run early morning and the evening. Keep a small sponge spider (fly) or a micro tube jig rigged through the warm months.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 1 to 6 ft | midday & dusk | Shallow bay flat (3 ft) | 1/32 oz jig + micro plastic, Tiny popper (evenings) |
| Summer | 4 to 15 ft | dawn & dusk | Shallow bay flat (3 ft) | Small sponge spider (fly), Micro tube jig |
| Fall | 6 to 18 ft | midday | Break off the point (9 ft) | Micro jig + waxworm, Small spoon tipped |
| Winter | 6 to 20 ft | midday | Deep basin (17 ft) | Tungsten ice jig + plastic, Tiny spoon |
When the water first warms, largemouth bass slide up into 2 to 10 ft. By summer they slide out to 8 to 20 ft, and by winter most fish are in 6 to 20 ft. If you only fish one area, make it Shallow bay flat: a weed flat around 3 ft that scores prime in spring. In summer the feeding windows fall in early morning and the evening. Keep a texas-rigged 10" worm or a deep-diving crankbait rigged through the warm months.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 2 to 10 ft | dawn & dusk | Shallow bay flat (3 ft) | Spinnerbait, Chatterbait |
| Summer | 8 to 20 ft | dawn & dusk | Break off the point (9 ft) | Texas-rigged 10" worm, Deep-diving crankbait |
| Fall | 4 to 15 ft | midday & dawn | Main-lake point (8 ft) | Squarebill crankbait (shad), Spinnerbait |
| Winter | 6 to 20 ft | midday | Break off the point (9 ft) | Blade bait, Jigging spoon |
Early season rainbow trout use the shallows, holding in 5 to 20 ft. Even in summer they hold at 5 to 20 ft; winter keeps them in 4 to 20 ft. The chart's best answer is Dam Creek inflow — inflow / creek mouth, 4 ft, prime for spring. Best bite is early morning and the evening. Tie on a dodger + spoon (deep troll) or a flutter spoon and you're in the game.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 5 to 20 ft | dawn & dusk | Dam Creek inflow (4 ft) | Inline spinner (silver), Small spoon |
| Summer | 5 to 20 ft | dawn & dusk | Dam Creek inflow (4 ft) | Dodger + spoon (deep troll), Flutter spoon |
| Fall | 6 to 20 ft | dawn & dusk | Main-lake point (8 ft) | Casting spoon, Jerkbait over shoals |
| Winter | 4 to 20 ft | dawn | Break off the point (9 ft) | Jigging spoon, Tube jig (white) |
Start shallow in spring: yellow perch sit in 3 to 12 ft that time of year. Summer pushes them deeper, 6 to 20 ft, and winter fish settle into 6 to 20 ft. The spot to know is Shallow bay flat, a weed flat in about 3 ft of water that rates prime for yellow perch in spring. Warm-month bites cluster around early morning. Throw a drop-shot micro plastics or a small spoon tipped with worm until the fish tell you otherwise.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | midday & dawn | Shallow bay flat (3 ft) | Small jig + curly tail, Perch-pattern micro crank |
| Summer | 6 to 20 ft | dawn | Deep basin (17 ft) | Drop-shot micro plastics, Small spoon tipped with worm |
| Fall | 6 to 20 ft | midday | Deep basin (17 ft) | Jigging spoon (small), Perch rig / spreader |
| Winter | 6 to 20 ft | midday & dawn | Deep basin (17 ft) | Tungsten jig + spikes, Rattle spoon (small) |
Come spring, look for smallmouth bass tight to the bank in 3 to 12 ft. Expect a summer slide to 6 to 20 ft, then a winter hold in 6 to 20 ft. Start at Main-lake point. It's a point holding about 8 ft of water and rates prime come fall. Prime time lands in early morning and the evening. A drop shot (goby/minnow) or a ned rig is the honest summer answer here.
| Season | Depth | Best window | Start at | Go-to baits |
|---|---|---|---|---|
| Spring | 3 to 12 ft | dawn & dusk | Main-lake point (8 ft) | Ned rig, Tube jig |
| Summer | 6 to 20 ft | dawn & dusk | Break off the point (9 ft) | Drop shot (goby/minnow), Ned rig |
| Fall | 6 to 20 ft | midday & dawn | Main-lake point (8 ft) | Jerkbait, Blade bait |
| Winter | 6 to 20 ft | midday | Break off the point (9 ft) | Blade bait, Hair jig |
Count 10 structure marks on this chart. The deepest, Deep basin, sits near 17 ft.
Access data: Utah DNR — Boat Ramps. Confirm conditions and fees locally before you launch.
| Date | Species | Count | Size |
|---|---|---|---|
| Feb 9 | Rainbow trout | 5,000 | ~9.8" |
| Sep 30, 2025 | Rainbow trout | 10,000 | ~10.4" |
Source: Utah DWR fish-stocking report, retrieved 2026-08-18.
Season dates, license requirements, and size and bag limits for Utah waters are set by the Utah Division of Wildlife Resources — and special regulations can apply to Mantua Reservoir specifically, so confirm the current rules before you fish.
Check the official Utah fishing regulations →
Mantua Reservoir is about 20 ft (6 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 bluegill, largemouth bass, rainbow trout, yellow perch, smallmouth bass on Mantua Reservoir.
Shallow bay flat is the top-rated area: a weed flat in about 3 ft of water that rates prime for bluegill in spring. The map above holds the full rated-spot list for every species and season.
For bluegill, 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 Utah DWR fish-stocking report records, Mantua Reservoir was most recently stocked Feb 9 with 5,000 rainbow trout. The full stocking history is listed above.
Fishing on Mantua Reservoir is regulated by the Utah Division of Wildlife Resources. Check the official Utah regulations for current license requirements, season dates, and size and bag limits — special regulations can apply to this specific water.
Hyrum Reservoir 9 mi · Porcupine Reservoir 10 mi · Willard Bay Reservoir 12 mi · Pineview Reservoir 17 mi · Causey Reservoir 23 mi · Newton Reservoir 28 mi · Birch Creek Reservoir 31 mi · Lost Creek Reservoir 36 mi · Lamont Reservoir 42 mi, ID · Foster Reservoir 43 mi, ID · Bear Lake 45 mi, UT/ID · East Canyon Reservoir 45 mi
See how Mantua Reservoir stacks up: best largemouth bass lakes in Utah · best smallmouth bass lakes in Utah · best bluegill lakes in Utah · best rainbow trout lakes in Utah
Browse all Utah 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.