Tulaby Lake
Tulaby Lake in Mahnomen County, Minnesota has a water quality grade of C (Fair). Water clarity: 7.8 ft visibility. Phosphorus: 23 µg/L. Chlorophyll-a (algae): 10.2 µg/L. Maximum depth: 43 ft. Surface area: 832.07 acres.
- Clarity
- 7.8 ft
- Typical in August
- 73°F
- Max depth
- 43 ft
- Area
- 832 acres
- Type
- Eutrophic
- Trend
- ↑ Improving
- Public access
- Yes
- Ice-out
- Apr 19
- Open water
- 218 days
Next lake in Mahnomen County
Free interactive depth-contour map of Tulaby Lake, reaching a maximum surveyed depth of 40 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.
Tulaby Lake is a 832-acre productive, nutrient-rich eutrophic lake in Mahnomen County, Minnesota with a maximum depth of 43 feet. Water quality is graded C based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. The lake supports 16 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 11 other monitored lakes in Mahnomen County, Tulaby Lake ranks #8 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-02. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyModerate
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Generally safe for swimming, moderate water quality
Water Quality Grade: C (Fair)
Moderate clarity, visible to about 7.8 ft. Phosphorus level: 23 µg/L. Chlorophyll-a: 10.2 µg/L. Trophic State Index: 50.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 7.8 ft | Not graded |
| Phosphorus | 23 µg/L | Good |
| Chlorophyll-a (Algae) | 10.2 µg/L | Fair |
| Trophic State Index (TSI) | 50 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Tulaby Lake
Compare lakeside cabins, hotels, and vacation rentals near Tulaby Lake in Mahnomen County, Minnesota — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Tulaby Lake
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Water Temperature
Tulaby Lake typically sits around 73°F at the surface in August. Summer average is about 72°F. Usually warmest in Jul (about 75°F) and coldest in May (about 58°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 180 field readings (2011–2025) via the EPA Water Quality Portal. See the full Tulaby Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Tulaby Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was high (159,956 cells/mL) on November 22, 2025.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 43 ft |
| Surface Area | 832 acres |
| Shoreline Length | 5.8 mi |
| Littoral Zone | 34% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Tulaby LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Tulaby Lake
DNR Fisheries Survey Summary
14 surveys on file from MN DNR Fisheries. Most recent: 2025-08-07 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Yellow Perch | 70.44 | 0.14 lb |
| JND | 14.26 | — |
| Bluegill | 12.71 | 0.29 lb |
| Walleye | 8.60 | 1.77 lb |
| Bluntnose Minnow | 8.24 | — |
| BKF | 6.93 | — |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
Length Distributions
Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.
Yellow Perch
Bluegill
Walleye
From the 2025-08-07 survey
Coldwater habitat is needed by certain fish species such as Cisco, particularly during summer stratification. One coldwater habitat measure, the temperature at which dissolved oxygen decreases to 3.0 mg/L (i.e., TDO3), can be used to indicate whether coldwater habitat conditions support Cisco. Water quality data were…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Tulaby Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — TulabyFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Tulaby (1944)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — TulabyFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — TulabyPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.083 m/yr | 6 |
| Phosphorus | ↑ Improving | -1.57 µg/L/yr | 6 |
| Chlorophyll-a | ↑ Improving | -0.71 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (64 observations).
Estimated open water season: 218 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2012-03-24 (2012) | 2013-05-13 (2013) |
| Ice-In | 1991-11-04 (1991) | 1999-12-16 (1999) |
Most recent ice-out: 2024-04-05
County Ranking
Ranked #8 of 12 lakes in Mahnomen County
Nearby Lakes With Higher Grades
Tulaby Lake holds Grade C. One nearby lake has a higher nutrient-and-algae grade — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Mahnomen County
Frequently asked questions about Tulaby Lake
What is the water quality grade for Tulaby Lake?
- Tulaby Lake in Mahnomen County, Minnesota has a water quality grade of C (Fair). Water clarity: 7.8 ft visibility. Phosphorus: 23 µg/L. Chlorophyll-a (algae): 10.2 µg/L. Maximum depth: 43 ft. Surface area: 832.07 acres.
Is Tulaby Lake safe to swim in?
- Generally safe for swimming, moderate water quality. Tulaby Lake has a water quality grade of C (Fair). Algae concentration (chlorophyll-a) is 10.2 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Tulaby Lake?
- Tulaby Lake typically sits around 73°F at the surface in August, from 180 EPA Water Quality Portal field readings (2011–2025). That is a typical value for the month, not a live reading.
How deep is Tulaby Lake?
- Tulaby Lake has a maximum depth of 43 feet. The lake covers 832.07 acres.
What fish are in Tulaby Lake?
- Fish species found in Tulaby Lake include black bullhead, black crappie, bluegill, brown bullhead, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, smallmouth bass, tullibee (cisco), walleye, white sucker, yellow bullhead, yellow perch. Tulaby Lake is located in Mahnomen County, Minnesota.
When does Tulaby Lake thaw?
- Tulaby Lake typically has ice-out around Apr 19. Ice typically forms around Nov 23. The open water season is approximately 218 days.
Does Tulaby Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Tulaby Lake (clouds, ice, or an off-season gap). The most recent reading was high (159,956 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Tulaby Lake?
- Tulaby Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Tulaby Lake. Public access is listed as yes.
Explore Tulaby Lake across LakeGrade
Depth, room, public access, and the state wake-sport rules
Fish species and top-graded lakes across Minnesota
Fish species and best lakes in Mahnomen County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its grade
Lakes in the Red River of the North Watershed, ranked by water quality
High nutrients, frequent algae, reduced clarity
Minnesota's cleanest and most-polluted lakes, ranked
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Where this data comes from
248 measurements from 3 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA209 samples · 2020–2025 - Minnesota Chippewa Tribe, Minnesota (White Earth Band) (Tribal)
WEARTH_WQX39 samples · 2023
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Turbidity by Nephelometry
Monitoring station identifiers (3)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory
Ice data from Minnesota DNR Climate