South Twin Lake
South Twin Lake in Itasca County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 14 ft visibility. Maximum depth: 40 ft. Surface area: 140.78 acres.
- Clarity
- 14 ft
- Typical in August
- 70°F
- Max depth
- 40 ft
- Area
- 141 acres
- Trend
- → Stable
- Public access
- Yes
Next lake in Itasca County
Why South Twin 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 South Twin 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.
South Twin Lake is a 141-acre lake in Itasca County, Minnesota with a maximum depth of 40 feet. The lake supports 13 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 2022-08-14. 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 South Twin Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Good clarity, visible to about 14 ft. Trophic State Index: 39.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 14 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 39 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near South Twin Lake
Compare lakeside cabins, hotels, and vacation rentals near South Twin Lake in Itasca 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 South Twin Lake
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Water Temperature
South Twin Lake typically sits around 70°F at the surface in August. Summer average is about 63°F. Usually warmest in Aug (about 70°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 39 field readings (2016–2022) via the EPA Water Quality Portal. See the full South Twin Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 40 ft |
| Surface Area | 141 acres |
| Shoreline Length | 2.9 mi |
| Littoral Zone | 45% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Holman LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing South Twin 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
5 surveys on file from MN DNR Fisheries. Most recent: 2008-08-04 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Largemouth Bass | 10.52 | 0.85 lb |
| Bluegill | 7.49 | 0.14 lb |
| Black Crappie | 6.59 | 0.3 lb |
| Northern Pike | 5.14 | 2.19 lb |
| Tullibee (Cisco) | 3.27 | 0.97 lb |
| Yellow Bass | 1.28 | 0.91 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.
Largemouth Bass
Bluegill
Black Crappie
Northern Pike
From the 2008-08-04 survey
South Twin is a 179 acre lake located just south of Marble, MN. Access can be obtained via North Twin Lake through the channel on the north side. The 2001 lake management plan indicated largemouth bass and northern pike were primary species for management while black crappie were secondary species. In 2008, the black…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for South Twin Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — South TwinFisheries 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 | -0.031 m/yr | 6 |
EPA Impairment Status
South Twin 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 MN31-0190-00 · Official waterbody report · Matched by proximity (0.92 km)
Graded lakes near South Twin Lake
South Twin Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Itasca County
Frequently asked questions about South Twin Lake
What is the water quality grade for South Twin Lake?
- South Twin Lake in Itasca County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 14 ft visibility. Maximum depth: 40 ft. Surface area: 140.78 acres.
Is South Twin Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. South Twin 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 South Twin Lake?
- South Twin Lake typically sits around 70°F at the surface in August, from 39 EPA Water Quality Portal field readings (2016–2022). That is a typical value for the month, not a live reading.
How deep is South Twin Lake?
- South Twin Lake has a maximum depth of 40 feet. The lake covers 140.78 acres.
What fish are in South Twin Lake?
- Fish species found in South Twin Lake include black crappie, bluegill, bowfin (dogfish), largemouth bass, northern pike, pumpkinseed, rock bass, shorthead redhorse, tullibee (cisco), walleye, white sucker, yellow bullhead, yellow perch. South Twin Lake is located in Itasca County, Minnesota.
Are there boat ramps on South Twin Lake?
- South Twin Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Holman Lake. Public access is listed as yes.
Explore South Twin Lake across LakeGrade
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Where this data comes from
11 measurements from 1 monitoring station, 2021–2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA11 samples · 2021–2022
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory