Charles Mill Reservoir
Ashland County, Ohio1,350 acresView mapDirections
Not Rated: three monitoring stations are on record, but they measured water clarity only. LakeQuality’s A–F method grades total phosphorus, total nitrogen, chlorophyll-a, and turbidity; clarity is shown, not scored.
- Public access
- Limited data
Charles Mill Reservoir in Ashland County, Ohio is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 0.9 ft visibility. Surface area: 1350 acres.
- Clarity
- 0.9 ft
- Typical in September
- 71°F
- Area
- 1,350 acres
- Trend
- ↑ Improving
- Public access
- Yes
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Watch Charles Mill Reservoir’s letter
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Free interactive depth-contour map of Charles Mill Reservoir, reaching a maximum surveyed depth of 27 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Ohio DNR.
Why Charles Mill Reservoir has no grade
Charles Mill Reservoir has monitoring on record from three stations, but only water clarity was measured. LakeQuality’s A–F letter uses total phosphorus, total nitrogen, chlorophyll-a, and turbidity against EPA National Lakes Assessment condition classes. With none of those grading measurements on record, Charles Mill Reservoir is Not Rated — not an F. Its 0.9-foot median from 39 readings collected 2020–2021 is still shown as clarity, but clarity alone cannot earn a letter.
Not Rated is EPA Integrated Reporting Category 3 — insufficient information. Everything below that has been measured is still reported on this page.
Sampling is run by Ohio EPA and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Charles Mill Reservoir is a 1,350-acre lake in Ashland County, Ohio. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available with 2 public boat landings.
Source: EPA Water Quality Portal sampling records, Ohio EPA, last sampled 2021-10-11. Grade methodology: LakeQuality methodology.
What Charles Mill Reservoir is good for
From access and monitoring records, not editorial picks.
- Boat launch2 documented ramps
- Camping3 public campgrounds nearby
- Big water1,350 acres
Swimming Safety
Not ratedLimited data
The letter is not a swimming clearance. Check local advisories before you swim.
Water quality measurements for Charles Mill Reservoir
These readings exist but are not enough for an A–F grade — see why.
Very murky, less than 0.9 ft of visibility. TSI 79.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 0.9 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 79 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Water Temperature
Charles Mill Reservoir typically sits around 71°F at the surface in September. Summer average is about 78°F. Usually warmest in Aug (about 79°F) and coldest in Oct (about 65°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 135 field readings (2010–2021) via the EPA Water Quality Portal. See the full Charles Mill Reservoir water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 1,350 acres |
| Public Access | Yes |
No bathymetric survey has been published for Charles Mill Reservoir, so its depth is not documented here.
Recreation & Access
- Charles Mill Boat RampPublic
- Charles Mill Lake Marina rampPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Public campgrounds near Charles Mill Reservoir
- Charles Mill Lake Park Main Campground0.3 km
- Charles Mill Lake Park Eagle Point Campground0.5 km
- Charles Mill Lake Park Beach Campground1.1 km
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
Fishing Charles Mill Reservoir
Water Quality Trend: ↑ Improving
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +5.72 m/yr | 2 |
Reservoir Info (USACE NID)
Charles Mill Reservoir is a man-made reservoir impounded by the Charles Mill Dam (completed 1936), built primarily for flood risk reduction on the BLACK FORK OF MOHICAN RIVER; earth-type dam, 52 ft tall and 1,390 ft long.
- Surface area
- 1,350 ac
- Normal storage
- 7,400 ac-ft
- Max storage
- 88,000 ac-ft
- Drainage area
- 215 sq mi
- Hazard class
- High
- Owner
- USACE - Huntington District
All listed purposes: Flood Risk Reduction;Fish and Wildlife Pond;Recreation.
Source: USACE National Inventory of Dams, NID ID OH00020 · Operator website
Regulated Pollution Sources Nearby
4 EPA-permitted facilities operate within about 5 miles of Charles Mill Reservoir under Clean Water Act (NPDES) discharge permits. 4 facilities have a reported Clean Water Act violation in the past three years.
- Charles Mill Lake CampgroundMansfield · 0.4 mi away · NPDES OH0146650Recent violation
- Village Of Mifflin WwtpMifflin · 0.9 mi away · NPDES OH0146501Recent violation
- Mwcd - Johnny Appleseed WwtpAshland · 2.1 mi away · NPDES OH0130443Recent violation
- Village Of Lucas WwtpLucas · 4.9 mi away · NPDES OH0021041Recent violation
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Graded lakes near Charles Mill Reservoir
Charles Mill Reservoir has no grade, but these lakes within a short drive do.
Nearby Lakes in Ashland County
Frequently asked questions about Charles Mill Reservoir
Where is Charles Mill Reservoir?
- Charles Mill Reservoir is a lake in Ashland County, Ohio. 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 Charles Mill Reservoir?
- Charles Mill Reservoir in Ashland County, Ohio is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 0.9 ft visibility. Surface area: 1350 acres.
Is Charles Mill Reservoir safe to swim in?
- The letter is not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Charles Mill Reservoir?
- Charles Mill Reservoir typically sits around 71°F at the surface in September, from 135 EPA Water Quality Portal field readings (2010–2021). That is a typical value for the month, not a live reading.
Are there boat ramps on Charles Mill Reservoir?
- Charles Mill Reservoir has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Charles Mill Boat Ramp, Charles Mill Lake Marina ramp. Public access is listed as yes.
Are there campgrounds on Charles Mill Reservoir?
- Charles Mill Reservoir has 3 public campgrounds from USGS The National Map within 5 km, including Charles Mill Lake Park Main Campground, Charles Mill Lake Park Eagle Point Campground, Charles Mill Lake Park Beach Campground. 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 Charles Mill Reservoir across LakeQuality
Depth, room, public access, and the state wake-sport rules
Species activity outlook by water temperature and season
Where to stay at Ohio's top lakes, each with its grade
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Where this data comes from
39 measurements from 3 monitoring stations, 2020–2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Ohio Lake Management Society (Volunteer)
OLMS39 samples · 2020–2021
Monitoring station identifiers (3)
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Named boat-access points from the USGS National Boat Ramps inventory
Public campgrounds from USGS The National Map Structures, within about 3 miles