Defiance Lake
Defiance Lake in McHenry County, Illinois is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 66 acres.
- Area
- 66 acres
Next lake in McHenry County
Swipe left or right on this bar to open the next or previous lake.
Why Defiance Lake has no grade
We grade a lake only when the monitoring record supports a letter: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Defiance Lake, no water-quality sampling on record for this lake.
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by Illinois EPA and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Defiance Lake is a 66-acre lake in McHenry County, Illinois.
Source: EPA Water Quality Portal sampling records, Illinois EPA, last sampled recent years. Grade methodology: LakeQuality methodology.
Watch Defiance Lake water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Swimming Safety
Not ratedElevated nutrients
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Defiance Lake
These readings exist but are not enough for an A–F grade — see why.
No clarity data. Trophic State Index: undefined.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) |
Where to stay near Defiance Lake
Compare lakeside cabins, hotels, and vacation rentals near Defiance Lake in McHenry 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.
Top-rated places to stay near Defiance Lake
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 →
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 66 acres |
No bathymetric survey has been published for Defiance Lake, so its depth is not documented here.
Recreation & Access
- Defiance LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Defiance Lake
Nearby Lakes in McHenry County
Frequently asked questions about Defiance Lake
Where is Defiance Lake?
- Defiance Lake is a lake in McHenry County, Illinois. LakeQuality has not rated this lake (UNRATED) — no water-quality sampling on record for this lake.
What is the water quality grade for Defiance Lake?
- Defiance Lake in McHenry County, Illinois is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 66 acres.
Is Defiance Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Defiance Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
Are there boat ramps on Defiance Lake?
- Defiance Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Defiance Lake.
Explore Defiance Lake across LakeQuality
Species activity outlook by water temperature and season
Top lakes and where to stay in the Chain O'Lakes area
Where to stay at Illinois's top lakes, each with its grade
Illinois's cleanest and most-polluted lakes, ranked
More Illinois Lake Rankings
Other Lakes in Illinois
Where this data comes from
Measurements for Defiance Lake come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.
Other records on this page
Named boat-access points from the USGS National Boat Ramps inventory