Cedar Lake
Slope County, North Dakota210 acresView mapDirections
ND DEQ publishes the water-quality measurements for Cedar Lake. Here is what has been measured.
- Hypereutrophic
- Impaired · Sediment / turbidity
- 12 ft max depth
- Public access
- Limited data
Cedar Lake in Slope County, North Dakota has water-quality measurements published by ND DEQ, shown here as reported. Water clarity: 1.3 ft visibility. Phosphorus: 136.5 µg/L. Chlorophyll-a (algae): 53.4 µg/L. Surface area: 210 acres.
Cedar Lake is a 210-acre highly nutrient-loaded hypereutrophic lake in Slope County, North Dakota with an estimated average depth of about 12 feet. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 1 other monitored lakes in Slope County, Cedar Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, NDDEQ, last sampled 2023-10-10. Methodology: how these readings are compared.
What Cedar Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming conditions
Readings onlyLimited data
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Cedar Lake is listed impaired under Clean Water Act §303(d) (IR 5) for sediment / turbidity. Check local advisories before you swim.
Whether Cedar Lake is safe to swim in today is a call for the North Dakota Department of Environmental Quality and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Cedar Lake
These are the measurements ND DEQ publishes for Cedar Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 1.3 ft of visibility. Phosphorus 136.5 µg/L. Chlorophyll-a 53.4 µg/L. TSI 73.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 1.3ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 137µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | 53.4µg/L | Measured, not scored The green pigment in algae — a direct measure of how much algae is in the water. |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 73 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Cedar Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Cedar Lake typically sits around 47°F at the surface in October. Summer average is about 67°F. Usually warmest in Jul (about 71°F) and coldest in Oct (about 47°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (47°F) to its warmest (71°F).
Typical surface water temperature by month, from 14 field readings (2023–2023) via the EPA Water Quality Portal. See the full Cedar Lake water temperature breakdown →
Lake Details
Max depth
~12 ft est.
Surface area
210 acres
Public access
Yes
Listed by ND DEQ
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 Cedar Lake.
Lake Size & Watershed
Watershed (drainage) area
229 sq mi
HydroLAKES / HydroSHEDS
Shoreline
2.9 mi
HydroLAKES / HydroSHEDS
Elevation
2,690 ft
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
- Cedar LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Cedar Lake
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Top-rated places to stay near Cedar Lake
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Fishing Cedar Lake
Reservoir Info (USACE NID)
Cedar Lake is a man-made reservoir impounded by the Cedar Lake Dam (completed 1935), built primarily for fish and wildlife pond on the Cedar Creek; earth-type dam, 23 ft tall and 723 ft long.
- Surface area
- 210 ac
- Normal storage
- 1,255 ac-ft
- Max storage
- 2,875 ac-ft
- Drainage area
- 208 sq mi
- Hazard class
- Low
- Owner
- ND Game & Fish
All listed purposes: Fish and Wildlife Pond;Recreation.
Source: USACE National Inventory of Dams, NID ID ND00122 · Operator website
EPA Impairment Status
Cedar Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit ND-10130205-003-L_00 · Official waterbody report
Nearby Lakes in Slope County
Frequently asked questions about Cedar Lake
Where is Cedar Lake?
- Cedar Lake is a lake in Slope County, North Dakota. Its water-quality measurements are published by ND DEQ and shown on this page as reported.
What is the water quality of Cedar Lake?
- Cedar Lake in Slope County, North Dakota has water-quality measurements published by ND DEQ, shown here as reported. Water clarity: 1.3 ft visibility. Phosphorus: 136.5 µg/L. Chlorophyll-a (algae): 53.4 µg/L. Surface area: 210 acres.
Is Cedar Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Cedar Lake is listed impaired under Clean Water Act §303(d) (IR 5) for sediment / turbidity. Check local advisories before you swim.
What is the water temperature of Cedar Lake?
- Cedar Lake typically sits around 47°F at the surface in October, from 14 EPA Water Quality Portal field readings (2023–2023). That is a typical value for the month, not a live reading.
How deep is Cedar Lake?
- No published bathymetric survey covers Cedar Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 12 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 210 acres.
Are there boat ramps on Cedar Lake?
- Cedar Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Cedar Lake. Public access is listed as yes.
Can I fish at Cedar Lake?
- Cedar Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by North Dakota's fish and wildlife agency, so check its current regulations before you go.
Explore Cedar Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
Species activity outlook by water temperature and season
Where to stay at North Dakota's top lakes, each with its readings
North Dakota's cleanest lakes, ranked on agency measurements
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Other Lakes in North Dakota
Hypereutrophic Lakes in North Dakota
Where this data comes from
21 measurements from 1 monitoring station, 2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- North Dakota Department Of Environmental Quality
21NDHDWQ_WQX21 samples · 2023
Analytical methods
- Phosphorus by Colorimetry
- 447.0 ~ EPA; Chlorophyll a and b in phytoplankton by HPLC/UV
- 4500 NO3 E ~ Nitrate in Water- Cadmium Reduction
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
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