Ruth Lake
Ruth Lake in Crow Wing County, Minnesota has a water quality grade of A (Excellent). Water clarity: 16 ft visibility. Phosphorus: 11 µg/L. Chlorophyll-a (algae): 2.7 µg/L. Maximum depth: 39 ft. Surface area: 599.2 acres.
- Clarity
- 16 ft
- Typical in August
- 72°F
- Max depth
- 39 ft
- Area
- 599 acres
- Type
- Oligotrophic
- Trend
- ↑ Improving
- Public access
- Yes
- Ice-out
- Apr 26
Next lake in Crow Wing County
Ruth Lake is a 599-acre cold, clear oligotrophic lake in Crow Wing County, Minnesota with a maximum depth of 39 feet. Water quality is graded A based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. The lake supports 12 documented fish species including black crappie, bluegill, and hybrid sunfish. Public access is available with 1 public boat landing. Compared to the 84 other monitored lakes in Crow Wing County, Ruth Lake ranks #60 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-14. 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)
Crystal clear, you can see 16 ft down. Phosphorus level: 11 µg/L. Chlorophyll-a: 2.7 µg/L. Trophic State Index: 39.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 16 ft | Not graded |
| Phosphorus | 11 µg/L | Good |
| Chlorophyll-a (Algae) | 2.7 µg/L | Good |
| Trophic State Index (TSI) | 39 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Ruth Lake
Compare lakeside cabins, hotels, and vacation rentals near Ruth 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
Ruth Lake typically sits around 72°F at the surface in August. Summer average is about 71°F. Usually warmest in Jul (about 74°F) and coldest in May (about 56°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 27 field readings (2017–2025) via the EPA Water Quality Portal. See the full Ruth Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 39 ft |
| Surface Area | 599 acres |
| Shoreline Length | 5.1 mi |
| Littoral Zone | 33% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Ruth LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Ruth 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
8 surveys on file from MN DNR Fisheries. Most recent: 2022-07-06 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 42.24 | 0.14 lb |
| Largemouth Bass | 30.36 | 0.87 lb |
| Yellow Bass | 26.17 | 0.58 lb |
| IOD | 20.22 | — |
| Bluntnose Minnow | 8.59 | — |
| Yellow Perch | 6.75 | 0.24 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
Yellow Bass
Yellow Perch
From the 2022-07-06 survey
A targeted survey of nearshore fish species in Ruth Lake was conducted on July 6-7, 2022, by Index of Biological Integrity (IBI) Program staff. Sampling sites were evenly spaced around the lake, and each was sampled by backpack electrofishing and seining with a 50-foot or 15-foot seine, where possible. Backpack…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Ruth Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — RuthFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Ruth (0233)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — RuthFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — RuthPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.177 m/yr | 6 |
| Phosphorus | ↑ Improving | -0.84 µg/L/yr | 6 |
| Chlorophyll-a | ↑ Improving | -1.03 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (7 observations).
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2015-04-12 (2015) | 2013-05-13 (2013) |
| Ice-In | 2017-11-21 (2017) | 2023-11-30 (2023) |
Most recent ice-out: 2018-05-02
EPA Impairment Status
Ruth 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 MN18-0212-00 · Official waterbody report
County Ranking
Ranked #60 of 85 lakes in Crow Wing County
Nearby Lakes in Crow Wing County
Frequently asked questions about Ruth Lake
What is the water quality grade for Ruth Lake?
- Ruth Lake in Crow Wing County, Minnesota has a water quality grade of A (Excellent). Water clarity: 16 ft visibility. Phosphorus: 11 µg/L. Chlorophyll-a (algae): 2.7 µg/L. Maximum depth: 39 ft. Surface area: 599.2 acres.
Is Ruth Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Ruth Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 2.7 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Ruth Lake?
- Ruth Lake typically sits around 72°F at the surface in August, from 27 EPA Water Quality Portal field readings (2017–2025). That is a typical value for the month, not a live reading.
How deep is Ruth Lake?
- Ruth Lake has a maximum depth of 39 feet. The lake covers 599.2 acres.
What fish are in Ruth Lake?
- Fish species found in Ruth Lake include black crappie, bluegill, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, smallmouth bass, walleye, white sucker, yellow bullhead, yellow perch. Ruth Lake is located in Crow Wing County, Minnesota.
When does Ruth Lake thaw?
- Ruth Lake typically has ice-out around Apr 26.
Are there boat ramps on Ruth Lake?
- Ruth Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Ruth Lake. Public access is listed as yes.
Explore Ruth Lake across LakeGrade
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Where this data comes from
81 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
MNPCA81 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- 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