Red Willow Lake
Griggs County, North DakotaView mapDirections
Not enough samples to grade — 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. No letter yet. Here is what we do have.
- 37 ft max depth
- Public access
- Limited data
Red Willow Lake in Griggs County, North Dakota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 6.4 ft visibility. Chlorophyll-a (algae): 6.8 µg/L.
- Clarity
- 6.4 ft
- Typical in August
- 73°F
- Max depth
- ~37 ft est.
- Chlorophyll-a
- 6.8 µg/L
- Trend
- ↓ Declining
- Public access
- Yes
Stays via Stay22
Stays near Red Willow Lake
Compare lakeside cabins, hotels, and vacation rentals near Red Willow Lake in Griggs County, North Dakota — 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 Red Willow Lake
Prices for Sep 11–13, 4 adults. Change dates on the map below.
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 North Dakota’s top lakes →
Watch Red Willow Lake’s letter
Email me if this lake’s grade moves. Grades stay free.
Or email
Why Red Willow Lake has no grade
We grade a lake only when the monitoring record supports a letter: 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 Red Willow 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 and algae (chlorophyll-a), but not phosphorus.
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 NDDEQ and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Red Willow Lake is a lake in Griggs County, North Dakota with an estimated average depth of about 37 feet. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, NDDEQ, last sampled 2025-10-23. Grade methodology: LakeQuality methodology.
What Red Willow Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming Safety
Not ratedLimited data
The letter is not a swimming clearance. Check local advisories before you swim.
Water quality measurements for Red Willow Lake
These readings exist but are not enough for an A–F grade — see why.
Murky, only visible to about 6.4 ft. Chlorophyll-a 6.8 µg/L. TSI 50.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 6.4 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | 6.8 µg/L | Not graded |
| Trophic State Index (TSI) | 50 | Mesotrophic |
Moderate nutrients, good water quality
Water Temperature
Red Willow Lake typically sits around 73°F at the surface in August. Summer average is about 67°F. Usually warmest in Aug (about 73°F) and coldest in Oct (about 49°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 21 field readings (2020–2025) via the EPA Water Quality Portal. See the full Red Willow Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~37 ft est. |
| Average Depth | ~12 ft est. |
| Public Access | Yes |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. North Dakota has not published bathymetry for Red Willow 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
- Red Willow LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Red Willow Lake
Water Quality Trend: ↓ Declining
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.086 m/yr | 2 |
Graded lakes near Red Willow Lake
Red Willow Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Griggs County
Frequently asked questions about Red Willow Lake
Where is Red Willow Lake?
- Red Willow Lake is a lake in Griggs County, North Dakota. LakeQuality has not rated this lake (UNRATED) — 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.
What is the water quality grade for Red Willow Lake?
- Red Willow Lake in Griggs County, North Dakota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 6.4 ft visibility. Chlorophyll-a (algae): 6.8 µg/L.
Is Red Willow Lake safe to swim in?
- The letter is not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Red Willow Lake?
- Red Willow Lake typically sits around 73°F at the surface in August, from 21 EPA Water Quality Portal field readings (2020–2025). That is a typical value for the month, not a live reading.
How deep is Red Willow Lake?
- No published bathymetric survey covers Red Willow Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 37 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Are there boat ramps on Red Willow Lake?
- Red Willow Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Red Willow Lake. Public access is listed as yes.
Explore Red Willow Lake across LakeQuality
More North Dakota Lake Rankings
Other Lakes in North Dakota
Mesotrophic Lakes in North Dakota
Where this data comes from
17 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- North Dakota Department Of Environmental Quality
21NDHDWQ_WQX17 samples · 2020–2025
Analytical methods
- Phosphorus by Colorimetry
- 447.0 ~ EPA; Chlorophyll a and b in phytoplankton by HPLC/UV
- 10200 H ~ Chlorophyll a-b-c Determination
- 4500 NO3 E ~ Nitrate in Water- Cadmium Reduction
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Depth, fish, and access data from North Dakota Game & Fish
Named boat-access points from the USGS National Boat Ramps inventory