Upper Gull Lake
Upper Gull Lake in Cass County, Minnesota has a water quality grade of A (Excellent). Water clarity: 9.5 ft visibility. Phosphorus: 20 µg/L. Chlorophyll-a (algae): 5.6 µg/L. Maximum depth: 54 ft. Surface area: 421.83 acres.
- Clarity
- 9.5 ft
- Typical in August
- 74°F
- Max depth
- 54 ft
- Area
- 422 acres
- Type
- Mesotrophic
- Trend
- ↓ Declining
- Public access
- No
- Ice-out
- Apr 25
- Open water
- 214 days
Next lake in Cass County
Upper Gull Lake is a 422-acre mesotrophic lake in Cass County, Minnesota with a maximum depth of 54 feet. Water quality is graded A based on 2 sampling years through 2025. Overall water quality is declining over recent sampling years. The lake supports 20 documented fish species including black bullhead, black crappie, and bluegill. No public access — the lake is private or restricted. Compared to the 103 other monitored lakes in Cass County, Upper Gull Lake ranks #12 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-29. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLimited data
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.
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A (Excellent)
Moderate clarity, visible to about 9.5 ft. Phosphorus level: 20 µg/L. Chlorophyll-a: 5.6 µg/L. Trophic State Index: 47.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 9.5 ft | Not graded |
| Phosphorus | 20 µg/L | Good |
| Chlorophyll-a (Algae) | 5.6 µg/L | Good |
| Trophic State Index (TSI) | 47 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Upper Gull Lake
Compare lakeside cabins, hotels, and vacation rentals near Upper Gull Lake in Cass 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.
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Water Temperature
Upper Gull Lake typically sits around 74°F at the surface in August. Summer average is about 72°F. Usually warmest in Jul (about 75°F) and coldest in May (about 62°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 67 field readings (2022–2025) via the EPA Water Quality Portal. See the full Upper Gull Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Upper Gull Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was moderate (92,045 cells/mL) on April 26, 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 | 54 ft |
| Surface Area | 422 acres |
| Shoreline Length | 8.6 mi |
| Littoral Zone | 37% |
| Public Access | No |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Upper Gull Lake
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
DNR Fisheries Survey Summary
11 surveys on file from MN DNR Fisheries. Most recent: 2025-06-23 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| MMS | 43.97 | — |
| Bluegill | 24.26 | 0.14 lb |
| GOS | 11.34 | 0.1 lb |
| Bluntnose Minnow | 10.98 | — |
| Tullibee (Cisco) | 7.47 | 1.06 lb |
| Yellow Perch | 7.16 | 0.12 lb |
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.
Bluegill
Tullibee (Cisco)
Yellow Perch
From the 2025-06-23 survey
Upper Gull Lake is a 422-acre lake and is part of the Gull Chain of Lakes near the city of Nisswa in Cass County. Upper Gull can be accessed via navigable channels from Gull, Margaret and Ray Lakes. Largemouth Bass are the primary management species. Northern Pike, Black Crappie, and Bluegill are secondary management…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Upper Gull Lake. 2 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — Upper GullFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Upper Gull (1533)Aquatic Plant Report · MN DNR LakeFinder
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.117 m/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (12 observations).
Estimated open water season: 214 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2015-04-11 (2015) | 2008-05-11 (2008) |
| Ice-In | 2014-11-14 (2014) | 2024-12-12 (2024) |
Most recent ice-out: 2025-04-12
County Ranking
Ranked #12 of 104 lakes in Cass County
Nearby Lakes in Cass County
Frequently asked questions about Upper Gull Lake
What is the water quality grade for Upper Gull Lake?
- Upper Gull Lake in Cass County, Minnesota has a water quality grade of A (Excellent). Water clarity: 9.5 ft visibility. Phosphorus: 20 µg/L. Chlorophyll-a (algae): 5.6 µg/L. Maximum depth: 54 ft. Surface area: 421.83 acres.
Is Upper Gull Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Upper Gull Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 5.6 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Upper Gull Lake?
- Upper Gull Lake typically sits around 74°F at the surface in August, from 67 EPA Water Quality Portal field readings (2022–2025). That is a typical value for the month, not a live reading.
How deep is Upper Gull Lake?
- Upper Gull Lake has a maximum depth of 54 feet. The lake covers 421.83 acres.
What fish are in Upper Gull Lake?
- Fish species found in Upper Gull Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, brown trout, common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, shorthead redhorse, smallmouth bass, tullibee (cisco), walleye, white sucker, yellow bullhead, yellow perch. Upper Gull Lake is located in Cass County, Minnesota.
When does Upper Gull Lake thaw?
- Upper Gull Lake typically has ice-out around Apr 25. Ice typically forms around Nov 25. The open water season is approximately 214 days.
Does Upper Gull Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Upper Gull Lake (clouds, ice, or an off-season gap). The most recent reading was moderate (92,045 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Explore Upper Gull Lake across LakeGrade
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Where this data comes from
119 measurements from 2 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
MNPCA119 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H 2 ~ Chlorophyll a-b-c Determination by spectrophotometer
Monitoring station identifiers (2)
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
Ice data from Minnesota DNR Climate