Upper Cullen Lake
Upper Cullen Lake in Crow Wing County, Minnesota has a water quality grade of A (Excellent). Water clarity: 8.7 ft visibility. Phosphorus: 23 µg/L. Chlorophyll-a (algae): 6.8 µg/L. Maximum depth: 40 ft. Surface area: 441.47 acres.
- Clarity
- 8.7 ft
- Typical in August
- 75°F
- Max depth
- 40 ft
- Area
- 441 acres
- Type
- Mesotrophic
- Trend
- → Stable
- Public access
- Yes
- Ice-out
- Apr 12
- Open water
- 226 days
Next lake in Crow Wing County
Upper Cullen Lake is a 441-acre mesotrophic lake in Crow Wing County, Minnesota with a maximum depth of 40 feet. Water quality is graded A based on 2 sampling years through 2025. The lake supports 14 documented fish species including black crappie, bluegill, and bowfin (dogfish). Public access is available with 1 public boat landing. Compared to the 84 other monitored lakes in Crow Wing County, Upper Cullen Lake ranks #56 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-20. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLow algae
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 8.7 ft. Phosphorus level: 23 µg/L. Chlorophyll-a: 6.8 µg/L. Trophic State Index: 48.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 8.7 ft | Not graded |
| Phosphorus | 23 µg/L | Good |
| Chlorophyll-a (Algae) | 6.8 µg/L | Good |
| Trophic State Index (TSI) | 48 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Upper Cullen Lake
Compare lakeside cabins, hotels, and vacation rentals near Upper Cullen Lake in Crow Wing 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 Cullen Lake typically sits around 75°F at the surface in August. Summer average is about 74°F. Usually warmest in Jul (about 77°F) and coldest in May (about 61°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 36 field readings (2016–2025) via the EPA Water Quality Portal. See the full Upper Cullen Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 40 ft |
| Surface Area | 441 acres |
| Shoreline Length | 4.9 mi |
| Littoral Zone | 68% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Middle Cullen LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Upper Cullen Lake
DNR Fisheries Survey Summary
10 surveys on file from MN DNR Fisheries. Most recent: 2021-09-02 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluntnose Minnow | 23.16 | — |
| Bluegill | 17.08 | 0.18 lb |
| Largemouth Bass | 11.37 | 1.33 lb |
| JND | 6.48 | — |
| Tullibee (Cisco) | 6.03 | 0.76 lb |
| Northern Pike | 5.70 | 1.78 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
Largemouth Bass
Tullibee (Cisco)
Northern Pike
From the 2021-09-02 survey
Upper Cullen Lake is a 435 acre lake, with a maximum depth of 40', located 6 miles northeast of the town of Nisswa in Crow Wing County. Upper Cullen is located in the Crow Wing River watershed. A nearshore survey was conducted to assess the populations of both game and non-game fish species. Ten 100' long sampling…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Upper Cullen Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — Upper CullenFisheries Lake Survey · MN DNR LakeFinder
Water Quality Trend: → Stable
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.049 m/yr | 6 |
| Phosphorus | → Stable | -0.16 µg/L/yr | 6 |
| Chlorophyll-a | → Stable | -0.04 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (29 observations).
Estimated open water season: 226 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2016-03-08 (2016) | 2022-05-02 (2022) |
| Ice-In | 2002-11-15 (2002) | 2007-12-01 (2007) |
Most recent ice-out: 2024-03-29
EPA Impairment Status
Upper Cullen Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit MN18-0351-00 · Official waterbody report · Matched by proximity (2.79 km)
County Ranking
Ranked #56 of 85 lakes in Crow Wing County
Nearby Lakes in Crow Wing County
Frequently asked questions about Upper Cullen Lake
What is the water quality grade for Upper Cullen Lake?
- Upper Cullen Lake in Crow Wing County, Minnesota has a water quality grade of A (Excellent). Water clarity: 8.7 ft visibility. Phosphorus: 23 µg/L. Chlorophyll-a (algae): 6.8 µg/L. Maximum depth: 40 ft. Surface area: 441.47 acres.
Is Upper Cullen Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Upper Cullen Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 6.8 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Upper Cullen Lake?
- Upper Cullen Lake typically sits around 75°F at the surface in August, from 36 EPA Water Quality Portal field readings (2016–2025). That is a typical value for the month, not a live reading.
How deep is Upper Cullen Lake?
- Upper Cullen Lake has a maximum depth of 40 feet. The lake covers 441.47 acres.
What fish are in Upper Cullen Lake?
- Fish species found in Upper Cullen Lake include black crappie, bluegill, bowfin (dogfish), brown bullhead, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, smallmouth bass, walleye, yellow bullhead, yellow perch. Upper Cullen Lake is located in Crow Wing County, Minnesota.
When does Upper Cullen Lake thaw?
- Upper Cullen Lake typically has ice-out around Apr 12. Ice typically forms around Nov 24. The open water season is approximately 226 days.
Are there boat ramps on Upper Cullen Lake?
- Upper Cullen Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Middle Cullen Lake. Public access is listed as yes.
Explore Upper Cullen Lake across LakeGrade
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Where this data comes from
80 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA80 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 (1)
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
Impairment status from EPA ATTAINS 303(d) database
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