State Line Lake
State Line Lake in Freeborn County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 5.2 ft visibility. Surface area: 371.95 acres.
- Clarity
- 5.2 ft
- Typical in August
- 72°F
- Mean depth
- ~9 ft est.
- Area
- 372 acres
- Public access
- Yes
- Ice-out
- Mar 20
Next lake in Freeborn County
Why State Line Lake has no grade
We grade a lake only when its monitoring record clears the evidence bar: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For State Line Lake, the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity. Sampling here has recorded water clarity, but not phosphorus and algae (chlorophyll-a).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by MPCA and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
State Line Lake is a 372-acre lake in Freeborn County, Minnesota with an estimated average depth of about 9 feet. The lake supports 5 documented fish species including black bullhead, bluegill, and common carp. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2022-10-01. Grade methodology: LakeGrade methodology.
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for State Line Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Murky, only visible to about 5.2 ft. Trophic State Index: 53.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5.2 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 53 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near State Line Lake
Compare lakeside cabins, hotels, and vacation rentals near State Line Lake in Freeborn 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
State Line Lake typically sits around 72°F at the surface in August. Summer average is about 74°F. Usually warmest in Jul (about 77°F) and coldest in May (about 60°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 12 field readings (2016–2019) via the EPA Water Quality Portal. See the full State Line Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Average Depth | ~9 ft est. |
| Surface Area | 372 acres |
| Shoreline Length | 3.8 mi |
| Public Access | Yes |
Depth marked “est.” is a modeled estimate from HydroLAKES, not a measured survey. Minnesota has not published bathymetry for State Line Lake.
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Recreation & Access
- State Line LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing State Line Lake
DNR Fisheries Survey Summary
1 survey on file from MN DNR Fisheries. Most recent: 2017-09-12 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Black Bullhead | 212.67 | 0.02 lb |
| Common Carp | 15.67 | 1.74 lb |
| Northern Pike | 7.00 | 3.69 lb |
| Yellow Perch | 5.33 | 0.47 lb |
| Bluegill | 2.67 | 0.21 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.
Black Bullhead
Common Carp
Northern Pike
Yellow Perch
From the 2017-09-12 survey
State Line Lake is a 446 acre shallow lake located near the southern Minnesota border on the north side of the town of State Line in Freeborn County. It is managed cooperatively with DNR Wildlife primarily for duck hunting and secondarily for fishing. The primary management species are Northern Pike and Yellow Perch…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for State Line Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — State LineFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — State LineFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — State LinePublic Water Access Sites · MN DNR LakeFinder
Ice Season
Historical ice data from Minnesota DNR (5 observations).
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2016-03-12 (2016) | 2018-04-28 (2018) |
| Ice-In | 2014-11-11 (2014) | 2017-12-09 (2017) |
Most recent ice-out: 2018-04-28
Reservoir Info (USACE NID)
State Line Lake is a man-made reservoir impounded by the State Line Lake (completed 1930), built primarily for fish and wildlife pond on the Winnebago River-TR; gravity-type dam, 8 ft tall and 60 ft long.
- Surface area
- 425 ac
- Normal storage
- 143 ac-ft
- Max storage
- 143 ac-ft
- Drainage area
- 10 sq mi
- Hazard class
- Low
- Owner
- County of Freeborn
Source: USACE National Inventory of Dams, NID ID MN01302 · Operator website
EPA Impairment Status
State Line 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 MN24-0030-00 · Official waterbody report
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of State Line Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Emmons WwtpEmmons · 1 mi away · NPDES MN0023311Recent violation
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Graded lakes near State Line Lake
State Line Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Freeborn County
Frequently asked questions about State Line Lake
What is the water quality grade for State Line Lake?
- State Line Lake in Freeborn County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 5.2 ft visibility. Surface area: 371.95 acres.
Is State Line Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. State Line Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
What is the water temperature of State Line Lake?
- State Line Lake typically sits around 72°F at the surface in August, from 12 EPA Water Quality Portal field readings (2016–2019). That is a typical value for the month, not a live reading.
How deep is State Line Lake?
- No published bathymetric survey covers State Line Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 9 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 371.95 acres.
What fish are in State Line Lake?
- Fish species found in State Line Lake include black bullhead, bluegill, common carp, northern pike, yellow perch. State Line Lake is located in Freeborn County, Minnesota.
When does State Line Lake thaw?
- State Line Lake typically has ice-out around Mar 20.
Are there boat ramps on State Line Lake?
- State Line Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include State Line Lake. Public access is listed as yes.
Explore State Line Lake across LakeGrade
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Where this data comes from
6 measurements from 1 monitoring station, 2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA6 samples · 2022
Analytical methods
- Field measurement/observation, generic method
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
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