Sibley Lake
Sheridan County, Wyoming34 acresView mapDirections
Wyoming DEQ publishes the water-quality measurements for Sibley Lake. Here is what has been measured.
- Mesotrophic
- 13 ft max depth
- Public access
- Limited data
Sibley Lake in Sheridan County, Wyoming has water-quality measurements published by Wyoming DEQ, shown here as reported. Water clarity: 9.2 ft visibility. Phosphorus: 10 µg/L. Surface area: 34 acres.
Sibley Lake is a 34-acre mesotrophic lake in Sheridan County, Wyoming with an estimated average depth of about 13 feet. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 4 other monitored lakes in Sheridan County, Sibley Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Wyoming DEQ, last sampled 2019-09-10. Methodology: how these readings are compared.
Sibley Lake covers about 34 acres in Sheridan County. It has one public boat landing. For a place on the water, look through cabin and lake-house rentals near Sibley Lake on Vrbo. For a hotel or motel room, Booking.com and Expedia both search around the lake.
What Sibley Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Camping4 public campgrounds nearby
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. Check local advisories before you swim.
Whether Sibley Lake is safe to swim in today is a call for the Wyoming Department of Environmental Quality and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Sibley Lake
These are the measurements Wyoming DEQ publishes for Sibley Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Moderate clarity, visible to about 9.2 ft. Phosphorus 10 µg/L. TSI 41.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 9.2ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 10µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | No reading 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. | 41 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Sibley Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~13 ft est.
Surface area
34 acres
Public access
Yes
Listed by Wyoming DEQ
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Wyoming has not published bathymetry for Sibley Lake.
Lake Size & Watershed
Watershed (drainage) area
6 sq mi
HydroLAKES / HydroSHEDS
Shoreline
1 mi
HydroLAKES / HydroSHEDS
Elevation
7,956 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
- Sibley LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Public campgrounds near Sibley Lake
Nearest public campgrounds in the USGS National Map inventory, within about 3 miles. An empty list means USGS records no campground that close, which is not the same as camping being unavailable. Where the source gives an official reservation link, it is used; the cabin and hotel search does not cover campsites. More camping lakes
Stays via Stay22
Stays near Sibley Lake
Compare lakeside cabins, hotels, and vacation rentals near Sibley Lake in Sheridan County, Wyoming — 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 Sibley Lake
Prices for Oct 30–Nov 1, 4 adults. Change dates on the map below.
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Fishing Sibley Lake
Reservoir Info (USACE NID)
Sibley Lake is a man-made reservoir impounded by the Sibley (completed 1938), built primarily for recreation on the Prune Creek; earth-type dam, 35 ft tall and 420 ft long.
- Surface area
- 34 ac
- Normal storage
- 379 ac-ft
- Max storage
- 635 ac-ft
- Drainage area
- 5 sq mi
- Hazard class
- High
- Owner
- USDA FS
All listed purposes: Recreation;Fish and Wildlife Pond.
Source: USACE National Inventory of Dams, NID ID WY01344 · Operator website
Nearby Lakes in Sheridan County
Frequently asked questions about Sibley Lake
Where is Sibley Lake?
- Sibley Lake is a lake in Sheridan County, Wyoming. Its water-quality measurements are published by Wyoming DEQ and shown on this page as reported.
What is the water quality of Sibley Lake?
- Sibley Lake in Sheridan County, Wyoming has water-quality measurements published by Wyoming DEQ, shown here as reported. Water clarity: 9.2 ft visibility. Phosphorus: 10 µg/L. Surface area: 34 acres.
Is Sibley Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Sibley Lake?
- No published bathymetric survey covers Sibley Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 13 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 34 acres.
Are there boat ramps on Sibley Lake?
- Sibley Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Sibley Lake. Public access is listed as yes.
Can I fish at Sibley Lake?
- Sibley 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 Wyoming's fish and wildlife agency, so check its current regulations before you go.
Are there campgrounds on Sibley Lake?
- Sibley Lake has 4 public campgrounds from USGS The National Map within 5 km, including Sibley Lake, Prune Creek, Pine Island Group Area, Pine Island. This is a location join, not a booking. Cabins and hotels are listed separately; campsite reservations use the official link when the source provides one.
Explore Sibley Lake across LakeQuality
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Where this data comes from
6 measurements from 1 monitoring station, 2019. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- State of Wyoming Department of Environmental Quality Watershed Program
WYDEQ_WATERSHED6 samples · 2019
Analytical methods
- Secchi
- Total Phosphorus After Block Digestion
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)
Named boat-access points from the USGS National Boat Ramps inventory
Public campgrounds from USGS The National Map Structures, within about 3 miles