Explosion Lake
Oconto County, WisconsinMesotrophic
Explosion Lake sits at the top of the Wisconsin DNR grading rubric with an A, a mark reached by the cleanest lakes in Wisconsin. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.
The lake sits in the mesotrophic zone — the band where most well-managed Wisconsin lakes fall. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. At 43 acres, Explosion Lake sits below the Wisconsin median: a small water where shoreline activity has an outsized effect on water quality. Explosion Lake ranks 3 of 62 in Oconto County, putting it in the upper tier of locally monitored lakes.
Eurasian watermilfoil is established at Explosion Lake, which can dampen recreational access and pressure the native plant community. Bass fishing is part of the appeal: the species list runs to 3, anchored by largemouth and/or smallmouth bass. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-08-07. Grade methodology: LakeGrade methodology.
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Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
Crystal clear, you can see 17 ft down. Phosphorus level: 15.7 µg/L. Trophic State Index: 40.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 17 ft | A |
| Phosphorus | 15.7 µg/L | A |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 40 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 43 acres |
Fish Species
Click a species to see every graded lake where it is documented.
→ Best fishing times for Explosion Lake (14-day solunar calendar)
→ Is it safe to eat fish from Explosion Lake? (mercury & PFAS guide)
→ Explosion Lake fishing regulations (limits, seasons, special rules)
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Water Quality Trend: → Stable
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.727 m/yr | 6 |
| Phosphorus | ↑ Improving | -1.38 µg/L/yr | 4 |
Location
County Ranking
Ranked #3 of 62 lakes in Oconto County
Nearby Lakes in Oconto County
More Wisconsin Lake Rankings
State Parks Near Explosion Lake
Other Grade A Lakes in Wisconsin
Washington County · Clarity: 11.8 ft
Washington County · Clarity: 12.6 ft
Walworth County · Clarity: 11 ft
Waukesha County · Clarity: 11.3 ft
Walworth County · Clarity: 20.2 ft
Kenosha County · Clarity: 10 ft
Mesotrophic Lakes in Wisconsin
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 2003. 4 stations on file (most recent sample 2025).
Fish Species (DNR-rated)
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Fish and recreation data from Wisconsin DNR Lakes
Most recent sample: 2025-08-07
Monitoring stations: 1
Where to stay near Explosion Lake
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