Minnesota · Carlton County
Thomson Reservoir Fishing guide
Thomson Reservoir is a 390-acre lake in Carlton County, Minnesota, reaching 22 ft at its deepest point. The Minnesota DNR has surveyed the lake 2 times, most recently in 2002, with walleye, smallmouth bass, northern pike and bluegill in the nets. That survey is 24 years old now.
DNR survey data
Fish species
The DNR last surveyed Thomson Reservoir in 2002. Ratings need a survey from the last 20 years, so this page lists the species from that older record without numbers.
- Walleye
- Smallmouth bass
- Northern pike
- Bluegill
- Crappie
- Yellow perch
- Rock bass
- Channel catfish
How to fish Thomson Reservoir through the year
Walleye
- Spring
- Walleye are shallow, on and just off the spawning flats and the first green weeds.
- Early summer
- Walleye are setting up on the outside weed edge, points and shallow structure.
- Summer
- Walleye are working the weed edge, points and any wind-blown structure. With 73% of this lake 15 ft or shallower, the weed edge is the main event.
- Fall
- Walleye are packing onto the sharpest breaks and points as the water cools, in big schools with short windows.
Smallmouth bass
- Spring
- Smallmouth are on shallow rock, gravel and sand where they spawn.
- Early summer
- Smallmouth are post-spawn on rock points, gravel bars and the adjacent breaks.
- Summer
- Smallmouth are on rock humps, points and hard-bottom breaks. With 73% of this lake 15 ft or shallower, the weed edge is the main event.
- Fall
- Smallmouth are bunched tight on deep rock, so find one and you have found the school.
Season patterns for each species. Open the live map for today's wind, light and water temp.
Suggested tackle
What to bring
Top presentations for this lake's structure and clarity:
Walleye · Trolling
Snap Weights + Stickbaits
4–5" suspending or slow-floating stickbait
Smallmouth bass · Soft plastics
Ned Rig
2.75" finesse stickbait or craw-style Ned bait
Smallmouth bass · Soft plastics
Drop Shot (Finesse Plastic)
4" finesse worm or 3" minnow-profile plastic
Northern pike · Soft plastics
Paddletail Swimbait on Jighead
4–5" paddletail swimbait on a ball-head swimbait jighead
Northern pike · Muskie & pike
Soft Rubber (Bull Dawg / Medusa)
10" soft rubber body bait
Full setups, including hooks, weights and line, are on the live map. As an Amazon Associate I earn from qualifying purchases.
MN DNR · in their words
From the 2002 survey
Thomson is a 339 acre reservoir located immediately north of Thomson, MN. It is operated as a water storage reservoir by Minnesota Power for the Thomson Hydro Station further down stream and is subject to water level manipulation. Maximum depth is 22 feet and 83% of the reservoir is shallower than 15 feet. Access is limited to a carry-down site at the north end of Thomson's main street. Walleye abundance of 4.2 per gillnet lift was above average compared to other Minnesota lakes of similar type. Mean length of walleye was 12.2 inches. Growth was slow, with length at age four of 13.3 inches. Six year-classes were represented from 1995 through 2001, with 82% of the fish from the 2000 and 2001 year-classes. Northern pike abundance of 0.8 per gillnet was below average compared to other Minnesota lakes of similar type. Mean length of northern pike was 19.2 inches. All year-classes were represented from 1998 through 2001. Smallmouth bass abundance of 3.2 per gillnet lift was higher than previous years, but there are no other similar lakes for comparison of catch rates. Mean length of smallmouth bass was 13.5 inches. Growth was fast, with length at age four of 12.0 inches. Seven year classes were represented from 1991 through 2001, with a strong 1998 year-class (44% of the fish). Yellow perch abundance of 2.8 per gillnet lift was below average compared to other Minnesota lakes of similar type. Mean length of perch was 8.6 inches. Growth was extremely fast, with length at age four of 9.4 inches. All year-classes were represented from 1997 through 2001. Eight channel catfish were captured during the assessment, but there are no similar lakes for comparison of catch rates. Channel catfish were large with a mean length of 26.0 inches. Walleye and smallmouth bass should currently provide excellent angling in Thomson Reservoir. Large yellow perch are also available in lower numbers. Other fish sampled included black bullhead, black crappie, rock bass, white sucker and shorthead redhorse.
Narrative text from the Minnesota DNR lake survey.
Recent reports
Thomson Reservoir fishing reports
Recent reports on Thomson Reservoir from guides, tournaments and regular anglers. Anything posted in the last two weeks also bumps the matching spots on the live map, so you'll see a "matches a recent report" tag on them.
Public water access
Getting on the water
- City access: City owned carry-down (over wall) at the northern terminus of Thomsons main street.
DNR bathymetry
Thomson Reservoir depth map
Within 30 miles
Nearby lakes
- Forbay Lake · 35 ac · 2.2 mi
- Scanlon Reservoir · 71 ac · 3 mi
- Chub Lake · 313 ac · 4.3 mi
- Fond du Lac Reservoir · 201 ac · 4.3 mi
- Hay Lake · 140 ac · 5.7 mi
- Blackhoof Lake · 41 ac · 10.8 mi
- Big Lake · 526 ac · 10.8 mi
- Hizer Lake · 34 ac · 11.3 mi
Quick answers
Frequently asked questions
How deep is Thomson Reservoir?
Thomson Reservoir reaches 22 ft at its deepest point; about 73% of the lake is littoral (15 ft or shallower).
How big is Thomson Reservoir?
Thomson Reservoir covers 390 acres with about 10.7 miles of shoreline.
What fish are in Thomson Reservoir?
Minnesota DNR surveys (most recently 2002) record walleye, smallmouth bass, northern pike, bluegill, crappie, yellow perch, rock bass, channel catfish.
Is Thomson Reservoir stocked?
No stocking is on record for Thomson Reservoir in the DNR's stocking database.
Does Thomson Reservoir have a public access?
Yes. Thomson Reservoir has one public access site: City access (City owned carry-down (over wall) at the northern terminus of Thomsons main street.).
When was Thomson Reservoir last surveyed?
The Minnesota DNR last surveyed Thomson Reservoir in 2002, the most recent of 2 surveys on record. That is more than 20 years ago, so this page lists species without ratings.
Page updated .
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