Mons Lake
Mons Lake in Todd County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 15.4 ft visibility. Phosphorus: 11 µg/L. Chlorophyll-a (algae): 2.8 µg/L. Maximum depth: 80 ft. Surface area: 94.52 acres.
- Clarity
- 15.4 ft
- Typical in August
- 58°F
- Max depth
- 80 ft
- Area
- 95 acres
- Public access
- Yes
Next lake in Todd County
Why Mons 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 Mons Lake, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). Sampling here has recorded water clarity, 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.
Mons Lake is a 95-acre lake in Todd County, Minnesota with a maximum depth of 80 feet. The lake supports 15 documented fish species including black crappie, bluegill, and bowfin (dogfish). Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2022-06-27. 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 Mons Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Crystal clear, you can see 15.4 ft down. Phosphorus level: 11 µg/L. Chlorophyll-a: 2.8 µg/L. Trophic State Index: 39.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 15.4 ft | Not graded |
| Phosphorus | 11 µg/L | Not graded |
| Chlorophyll-a (Algae) | 2.8 µg/L | Not graded |
| Trophic State Index (TSI) | 39 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Mons Lake
Compare lakeside cabins, hotels, and vacation rentals near Mons Lake in Todd 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 Mons Lake
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Water Temperature
Mons Lake typically sits around 58°F at the surface in August. Summer average is about 58°F. Usually warmest in Sep (about 65°F) and coldest in Jun (about 53°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 173 field readings (2016–2025) via the EPA Water Quality Portal. See the full Mons Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 80 ft |
| Surface Area | 95 acres |
| Shoreline Length | 1.8 mi |
| Littoral Zone | 22% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Mons LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Mons Lake
DNR Fisheries Survey Summary
14 surveys on file from MN DNR Fisheries. Most recent: 2024-08-15 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| JND | 40.00 | — |
| Largemouth Bass | 29.60 | 0.75 lb |
| Bluegill | 29.46 | 0.13 lb |
| LED | 10.36 | — |
| Tullibee (Cisco) | 10.25 | 0.51 lb |
| CNM | 9.70 | — |
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.
Largemouth Bass
Bluegill
Tullibee (Cisco)
From the 2024-08-15 survey
Temperature and dissolved oxygen measurements were collected from the deepest basin in Mons Lake on August 15th, 2024, to evaluate the quantity and quality of cold, oxygenated water (i.e., oxythermal habitat) available to Cisco, also known as Tullibee, the most sensitive coldwater species present in this lake. During…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Mons Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — MonsFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Mons (0898)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — MonsFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — MonsPublic Water Access Sites · MN DNR LakeFinder
EPA Impairment Status
Mons 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 MN77-0034-00 · Official waterbody report · Matched by proximity (1.33 km)
Graded lakes near Mons Lake
Mons Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Todd County
Frequently asked questions about Mons Lake
What is the water quality grade for Mons Lake?
- Mons Lake in Todd County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 15.4 ft visibility. Phosphorus: 11 µg/L. Chlorophyll-a (algae): 2.8 µg/L. Maximum depth: 80 ft. Surface area: 94.52 acres.
Is Mons Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Mons Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Algae concentration (chlorophyll-a) is 2.8 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Mons Lake?
- Mons Lake typically sits around 58°F at the surface in August, from 173 EPA Water Quality Portal field readings (2016–2025). That is a typical value for the month, not a live reading.
How deep is Mons Lake?
- Mons Lake has a maximum depth of 80 feet. The lake covers 94.52 acres.
What fish are in Mons Lake?
- Fish species found in Mons Lake include black crappie, bluegill, bowfin (dogfish), brown bullhead, green sunfish, hybrid sunfish, largemouth bass, muskellunge, northern pike, pumpkinseed, tullibee (cisco), walleye, white sucker, yellow bullhead, yellow perch. Mons Lake is located in Todd County, Minnesota.
Are there boat ramps on Mons Lake?
- Mons Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Mons Lake. Public access is listed as yes.
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Where this data comes from
4 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
MNPCA4 samples · 2022
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- 2120 B ~ Color in Water by Visual Comparison
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