Ninemile Lake
Ninemile Lake in Lake County, Minnesota has a water quality grade of A (Excellent). Water clarity: 6.6 ft visibility. Phosphorus: 17 µg/L. Chlorophyll-a (algae): 3.8 µg/L. Maximum depth: 40 ft. Surface area: 296.75 acres.
- Clarity
- 6.6 ft
- Typical in August
- 69°F
- Max depth
- 40 ft
- Area
- 297 acres
- Type
- Mesotrophic
- Trend
- → Stable
- Public access
- Yes
Next lake in Lake County
Ninemile Lake is a 297-acre mesotrophic lake in Lake County, Minnesota with a maximum depth of 40 feet. Water quality is graded A based on 2 sampling years through 2025. Phosphorus level is declining over recent sampling years. The lake supports 6 documented fish species including bluegill, northern pike, and pumpkinseed. Public access is available with 1 public boat landing. Compared to the 34 other monitored lakes in Lake County, Ninemile Lake ranks #13 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-29. Grade methodology: LakeGrade methodology.
Watch Ninemile Lake water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
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)
Murky, only visible to about 6.6 ft. Phosphorus level: 17 µg/L. Chlorophyll-a: 3.8 µg/L. Trophic State Index: 46.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 6.6 ft | Not graded |
| Phosphorus | 17 µg/L | Good |
| Chlorophyll-a (Algae) | 3.8 µg/L | Good |
| Trophic State Index (TSI) | 46 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Ninemile Lake
Compare lakeside cabins, hotels, and vacation rentals near Ninemile Lake in Lake 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 Ninemile Lake
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Minnesota’s top lakes →
Water Temperature
Ninemile Lake typically sits around 69°F at the surface in August. Summer average is about 68°F. Usually warmest in Aug (about 69°F) and coldest in May (about 58°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 106 field readings (2019–2025) via the EPA Water Quality Portal. See the full Ninemile Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 40 ft |
| Surface Area | 297 acres |
| Shoreline Length | 5.3 mi |
| Littoral Zone | 97% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Ninemile LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Ninemile Lake
DNR Fisheries Survey Summary
16 surveys on file from MN DNR Fisheries. Most recent: 2019-08-07 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluntnose Minnow | 24.00 | — |
| BNS | 16.92 | — |
| Yellow Perch | 13.36 | 0.22 lb |
| White Sucker | 8.38 | 1.89 lb |
| Walleye | 6.37 | 1.46 lb |
| Northern Pike | 3.67 | 1.71 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.
Yellow Perch
White Sucker
Walleye
Northern Pike
From the 2019-08-07 survey
A survey was completed in August 2019 to monitor the zooplankton community in Ninemile Lake. Samples were analyzed to provide baseline information on the zooplankton community composition and abundance and to determine if any aquatic invasive species have become established in the lake. Ninemile Lake was selected for…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Ninemile Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — NinemileFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Ninemile (0760)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — NinemileFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — NinemilePublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: → Stable
Based on 3 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | -0.006 m/yr | 3 |
| Phosphorus | ↓ Declining | +1.11 µg/L/yr | 3 |
| Chlorophyll-a | ↑ Improving | -0.91 µg/L/yr | 3 |
EPA Impairment Status
Ninemile 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 MN38-0033-00 · Official waterbody report
County Ranking
Ranked #13 of 35 lakes in Lake County
Nearby Lakes in Lake County
Frequently asked questions about Ninemile Lake
What is the water quality grade for Ninemile Lake?
- Ninemile Lake in Lake County, Minnesota has a water quality grade of A (Excellent). Water clarity: 6.6 ft visibility. Phosphorus: 17 µg/L. Chlorophyll-a (algae): 3.8 µg/L. Maximum depth: 40 ft. Surface area: 296.75 acres.
Is Ninemile Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Ninemile Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 3.8 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Ninemile Lake?
- Ninemile Lake typically sits around 69°F at the surface in August, from 106 EPA Water Quality Portal field readings (2019–2025). That is a typical value for the month, not a live reading.
How deep is Ninemile Lake?
- Ninemile Lake has a maximum depth of 40 feet. The lake covers 296.75 acres.
What fish are in Ninemile Lake?
- Fish species found in Ninemile Lake include bluegill, northern pike, pumpkinseed, walleye, white sucker, yellow perch. Ninemile Lake is located in Lake County, Minnesota.
Are there boat ramps on Ninemile Lake?
- Ninemile Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Ninemile Lake. Public access is listed as yes.
Explore Ninemile Lake across LakeGrade
Depth, room, public access, and the state wake-sport rules
2 documented falls within 9.8 mi, nearest Caribou Falls
Fish species and top-graded lakes across Minnesota
Fish species and best lakes in Lake County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its grade
Lakes in the Lake Superior Basin (MN+WI), ranked by water quality
Moderate nutrients, good water quality
Minnesota's cleanest and most-polluted lakes, ranked
More Minnesota Lake Rankings
State Parks Near Ninemile Lake
Other Grade A Lakes in Minnesota
Mesotrophic Lakes in Minnesota
Where this data comes from
41 measurements from 1 monitoring station, 2022–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA41 samples · 2022–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- 2130 B ~ Nephelometric Method
- 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