Marion Lake
Marion Lake in Dakota County, Minnesota has a water quality grade of A (Excellent). Water clarity: 7 ft visibility. Phosphorus: 20 µg/L. Chlorophyll-a (algae): 4.6 µg/L. Maximum depth: 21 ft. Surface area: 530.3 acres.
- Clarity
- 7 ft
- Typical in August
- 75°F
- Max depth
- 21 ft
- Area
- 530 acres
- Type
- Mesotrophic
- Trend
- → Stable
- Public access
- Yes
- Ice-out
- Mar 30
Next lake in Dakota County
Marion Lake is a 530-acre mesotrophic lake in Dakota County, Minnesota with a maximum depth of 21 feet. Water quality is graded A based on 2 sampling years through 2025. The lake supports 14 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 44 other monitored lakes in Dakota County, Marion Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-23. 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 7 ft. Phosphorus level: 20 µg/L. Chlorophyll-a: 4.6 µg/L. Trophic State Index: 47.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 7 ft | Not graded |
| Phosphorus | 20 µg/L | Good |
| Chlorophyll-a (Algae) | 4.6 µg/L | Good |
| Trophic State Index (TSI) | 47 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Marion Lake
Compare lakeside cabins, hotels, and vacation rentals near Marion Lake in Dakota 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
Marion Lake typically sits around 75°F at the surface in August. Summer average is about 76°F. Usually warmest in Jul (about 81°F) and coldest in Feb (about 38°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 169 field readings (2010–2025) via the EPA Water Quality Portal. See the full Marion Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 21 ft |
| Surface Area | 530 acres |
| Shoreline Length | 10.2 mi |
| Littoral Zone | 86% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Marion LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Marion 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
12 surveys on file from MN DNR Fisheries. Most recent: 2021-07-12 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 36.09 | 0.12 lb |
| Black Crappie | 14.73 | 0.16 lb |
| Black Bullhead | 9.31 | 0.7 lb |
| Yellow Perch | 7.83 | 0.14 lb |
| Yellow Bass | 6.94 | 0.67 lb |
| Largemouth Bass | 6.44 | 1.23 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
Black Crappie
Black Bullhead
Yellow Perch
From the 2021-07-12 survey
Lake Marion is a 530 acre class 35 lake in western Dakota County. Lake Marion is primarily managed for Walleye, and secondarily for Largemouth Bass, Northern Pike, and Bluegill. The City of Lakeville owns and maintains two park areas in the lake - Antler's Park on the SE corner and Casperson Park on the west side of…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Marion Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — MarionFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — MarionFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — MarionPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: → Stable
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | -0.008 m/yr | 4 |
Ice Season
Historical ice data from Minnesota DNR (16 observations).
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2024-03-03 (2024) | 2018-05-01 (2018) |
| Ice-In | 2008-11-24 (2008) | 2009-12-04 (2009) |
Most recent ice-out: 2026-03-28
EPA Impairment Status
Marion Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN19-0026-01 · Official waterbody report · Matched by proximity (0.08 km)
County Ranking
Ranked #1 of 45 lakes in Dakota County
Nearby Lakes in Dakota County
Frequently asked questions about Marion Lake
What is the water quality grade for Marion Lake?
- Marion Lake in Dakota County, Minnesota has a water quality grade of A (Excellent). Water clarity: 7 ft visibility. Phosphorus: 20 µg/L. Chlorophyll-a (algae): 4.6 µg/L. Maximum depth: 21 ft. Surface area: 530.3 acres.
Is Marion Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Marion Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 4.6 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Marion Lake?
- Marion Lake typically sits around 75°F at the surface in August, from 169 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
How deep is Marion Lake?
- Marion Lake has a maximum depth of 21 feet. The lake covers 530.3 acres.
What fish are in Marion Lake?
- Fish species found in Marion Lake include black bullhead, black crappie, bluegill, brown bullhead, common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, walleye, white sucker, yellow bullhead, yellow perch. Marion Lake is located in Dakota County, Minnesota.
When does Marion Lake thaw?
- Marion Lake typically has ice-out around Mar 30.
Are there boat ramps on Marion Lake?
- Marion Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Marion Lake. Public access is listed as yes.
Explore Marion Lake across LakeGrade
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Where this data comes from
58 measurements from 1 monitoring station, 2021–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA58 samples · 2021–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- Analysis of Chlorophyll in Periphyton and Plankton
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