Williamstown Lake
Grant County, Kentucky300 acresView mapDirections
Nutrients and algae sit mid-range for this region.
- Eutrophic
- #2 of 3 in the county
- 47 ft max depth
- Public access
Williamstown Lake in Grant County, Kentucky has a water quality grade of C (Fair). Phosphorus: 30 µg/L. Surface area: 300 acres.
- Max depth
- ~47 ft est.
- Area
- 300 acres
- Type
- Eutrophic
- Phosphorus
- 30 µg/L
- Trend
- ↓ Declining
- Public access
- Yes
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Williamstown Lake is a 300-acre productive, nutrient-rich eutrophic lake in Grant County, Kentucky with an estimated average depth of about 47 feet. Water quality is graded C based on 1 sampling years through 2022. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 2 other monitored lakes in Grant County, Williamstown Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, KY DOW, last sampled 2022-09-22. Grade methodology: LakeQuality methodology.
What Williamstown Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming Safety
Grade onlyModerate
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.
The C is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Water Quality Grade: C (Fair)
No clarity data. Phosphorus 30 µg/L. TSI 53. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 30 µg/L | Fair |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 53 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~47 ft est. |
| Average Depth | ~18 ft est. |
| Surface Area | 300 acres |
| Public Access | Yes |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Kentucky has not published bathymetry for Williamstown 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
- Ruby's Boat DockPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Williamstown Lake
Water Quality Trend: ↓ Declining
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Phosphorus | ↓ Declining | +2.47 µg/L/yr | 2 |
Reservoir Info (USACE NID)
Williamstown Lake is a man-made reservoir impounded by the Williamstown Lake Dam (completed 1957), built primarily for water supply on the Grassy Creek; earth-type dam, 62 ft tall and 680 ft long.
- Surface area
- 300 ac
- Normal storage
- 6,200 ac-ft
- Max storage
- 8,600 ac-ft
- Drainage area
- 8.65 sq mi
- Hazard class
- Significant
- Owner
- CITY OF WILLIAMSTOWN
Source: USACE National Inventory of Dams, NID ID KY00080 · Operator website
County Ranking
Ranked #2 of 3 lakes in Grant County
Nearby Lakes in Grant County
Frequently asked questions about Williamstown Lake
Where is Williamstown Lake?
- Williamstown Lake is a lake in Grant County, Kentucky. LakeQuality grades it C for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Williamstown Lake?
- Williamstown Lake in Grant County, Kentucky has a water quality grade of C (Fair). Phosphorus: 30 µg/L. Surface area: 300 acres.
Is Williamstown Lake safe to swim in?
- The C is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
How deep is Williamstown Lake?
- No published bathymetric survey covers Williamstown Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 47 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 300 acres.
Are there boat ramps on Williamstown Lake?
- Williamstown Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Ruby's Boat Dock. Public access is listed as yes.
Explore Williamstown Lake across LakeQuality
More Kentucky Lake Rankings
Other Grade C Lakes in Kentucky
Eutrophic Lakes in Kentucky
Where this data comes from
36 measurements from 4 monitoring stations, 2014–2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- KY WQX
21KY_WQX36 samples · 2014–2022
Analytical methods
- Phosphorus by Colorimetry
- Total Phosphorus After Block Digestion
- Turbidity by Nephelometry
Monitoring station identifiers (4)
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)
Named boat-access points from the USGS National Boat Ramps inventory