Greenfield Lake
Greene County, Illinois52 acresView mapDirections
Illinois EPA publishes the water-quality measurements for Greenfield Lake. Here is what has been measured.
- Eutrophic
- 24 ft max depth
- Public access
- Limited data
Greenfield Lake in Greene County, Illinois has water-quality measurements published by Illinois EPA, shown here as reported. Phosphorus: 85.5 µg/L. Chlorophyll-a (algae): 30 µg/L. Surface area: 52 acres.
Greenfield Lake is a 52-acre productive, nutrient-rich eutrophic lake in Greene County, Illinois with an estimated average depth of about 24 feet. Limited fish-species data available. Public access is available.
Source: EPA Water Quality Portal sampling records, Illinois EPA, last sampled 2021-10-19. Methodology: how these readings are compared.
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 Greenfield Lake is safe to swim in today is a call for the Illinois Environmental Protection Agency and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Greenfield Lake
These are the measurements Illinois EPA publishes for Greenfield Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. Phosphorus 85.5 µg/L. Chlorophyll-a 30 µg/L. TSI 66.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer. | |
| Total phosphorus | 85.5µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 30µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 66 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Greenfield Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Greenfield Lake typically sits around 62°F at the surface in October. Summer average is about 78°F. Usually warmest in Jul (about 83°F) and coldest in Apr (about 54°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (54°F) to its warmest (83°F).
Typical surface water temperature by month, from 176 field readings (2014–2021) via the EPA Water Quality Portal. See the full Greenfield Lake water temperature breakdown →
Lake Details
Max depth
~24 ft est.
Surface area
52 acres
Public access
Yes
Listed by Illinois EPA
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Illinois has not published bathymetry for Greenfield Lake.
Lake Size & Watershed
Watershed (drainage) area
8 sq mi
HydroLAKES / HydroSHEDS
Shoreline
1.6 mi
HydroLAKES / HydroSHEDS
Elevation
574 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.
Stays via Stay22
Stays near Greenfield Lake
Compare lakeside cabins, hotels, and vacation rentals near Greenfield Lake in Greene County, Illinois — 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. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around Greenfield Lake are listed below.
Top-rated places to stay near Greenfield Lake
Prices for Oct 23–25, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Illinois’s top lakes →
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Fishing Greenfield Lake
Reservoir Info (USACE NID)
Greenfield Lake is a man-made reservoir impounded by the Greenfield City Dam (completed 1959), built primarily for water supply on the TRIB RUBICON CREEK; earth-type dam, 33 ft tall and 650 ft long.
- Surface area
- 52 ac
- Normal storage
- 564 ac-ft
- Max storage
- 899 ac-ft
- Drainage area
- 1.1 sq mi
- Hazard class
- Significant
- Owner
- CITY OF GREENFIELD
Source: USACE National Inventory of Dams, NID ID IL00761 · Operator website · Matched by proximity (0.31 km)
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Greenfield Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Greenfield Stp, City OfGreenfield · 0.3 mi away · NPDES IL0029076Recent 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.
Nearby Lakes in Greene County
Frequently asked questions about Greenfield Lake
Where is Greenfield Lake?
- Greenfield Lake is a lake in Greene County, Illinois. Its water-quality measurements are published by Illinois EPA and shown on this page as reported.
What is the water quality of Greenfield Lake?
- Greenfield Lake in Greene County, Illinois has water-quality measurements published by Illinois EPA, shown here as reported. Phosphorus: 85.5 µg/L. Chlorophyll-a (algae): 30 µg/L. Surface area: 52 acres.
Is Greenfield 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 Greenfield Lake?
- Greenfield Lake typically sits around 62°F at the surface in October, from 176 EPA Water Quality Portal field readings (2014–2021). That is a typical value for the month, not a live reading.
How deep is Greenfield Lake?
- No published bathymetric survey covers Greenfield Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 24 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 52 acres.
Can I fish at Greenfield Lake?
- Public access to Greenfield Lake is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by Illinois's fish and wildlife agency, so check its current regulations before you go.
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Where this data comes from
40 measurements from 2 monitoring stations, 2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- illinois epa
IL_EPA_WQX40 samples · 2021
Analytical methods
- Phosphorus by Colorimetry
- 10200 H 2 ~ Chlorophyll a-b-c Determination by spectrophotometer
Monitoring station identifiers (2)
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)