Sprague Lake
Sargent County, North Dakota58 acresView mapDirections
ND DEQ publishes the water-quality measurements for Sprague Lake. Here is what has been measured.
- 63 ft max depth
- Public access
- Limited data
Sprague Lake in Sargent County, North Dakota has water-quality measurements published by ND DEQ, shown here as reported. Water clarity: 1.6 ft visibility. Chlorophyll-a (algae): 43.4 µg/L. Surface area: 58 acres.
Sprague Lake is a 58-acre lake in Sargent County, North Dakota with an estimated average depth of about 63 feet. Limited fish-species data available. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, NDDEQ, last sampled 2020-10-02. Methodology: how these readings are compared.
What Sprague Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Sprague 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 Sprague Lake
These are the measurements ND DEQ publishes for Sprague 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 1.6 ft of visibility. Chlorophyll-a 43.4 µg/L. TSI 69.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 1.6ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| Chlorophyll-a (algae) | 43.4µg/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. | 69 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Sprague Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Sprague Lake typically sits around 49°F at the surface in October. Summer average is about 67°F. Usually warmest in Jul (about 71°F) and coldest in Oct (about 49°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (49°F) to its warmest (71°F).
Typical surface water temperature by month, from 15 field readings (2010–2020) via the EPA Water Quality Portal. See the full Sprague Lake water temperature breakdown →
Lake Details
Max depth
~63 ft est.
Surface area
58 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 Sprague Lake.
Lake Size & Watershed
Watershed (drainage) area
38 sq mi
HydroLAKES / HydroSHEDS
Shoreline
2.9 mi
HydroLAKES / HydroSHEDS
Elevation
1,204 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
- Sprague 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 Sprague Lake
Compare lakeside cabins, hotels, and vacation rentals near Sprague Lake in Sargent 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 Sprague Lake
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Fishing Sprague Lake
Reservoir Info (USACE NID)
Sprague Lake is a man-made reservoir impounded by the Lake Mann Dam (completed 1965), built primarily for fish and wildlife pond on the Wild Rice River; earth-type dam, 9 ft tall and 784 ft long.
- Surface area
- 58 ac
- Normal storage
- 475 ac-ft
- Max storage
- 658 ac-ft
- Drainage area
- 0.18 sq mi
- Hazard class
- Low
- Owner
- US FISH AND WILDLIFE SERVICE
Source: USACE National Inventory of Dams, NID ID ND00900 · Operator website · Matched by proximity (0.8 km)
Nearby Lakes in Sargent County
Frequently asked questions about Sprague Lake
Where is Sprague Lake?
- Sprague Lake is a lake in Sargent 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 Sprague Lake?
- Sprague Lake in Sargent County, North Dakota has water-quality measurements published by ND DEQ, shown here as reported. Water clarity: 1.6 ft visibility. Chlorophyll-a (algae): 43.4 µg/L. Surface area: 58 acres.
Is Sprague Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Sprague Lake?
- Sprague Lake typically sits around 49°F at the surface in October, from 15 EPA Water Quality Portal field readings (2010–2020). That is a typical value for the month, not a live reading.
How deep is Sprague Lake?
- No published bathymetric survey covers Sprague Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 63 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 58 acres.
Are there boat ramps on Sprague Lake?
- Sprague Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Sprague Lake. Public access is listed as yes.
Can I fish at Sprague Lake?
- Sprague 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.
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Where this data comes from
9 measurements from 1 monitoring station, 2020. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- North Dakota Department Of Environmental Quality
21NDHDWQ_WQX9 samples · 2020
Analytical methods
- 447.0 ~ EPA; Chlorophyll a and b in phytoplankton by HPLC/UV
- 10200 H ~ Chlorophyll a-b-c Determination
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
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