Morgan Lake
Florence County, WisconsinOligotrophic
Morgan Lake earns an A — water clarity, phosphorus, and chlorophyll-a all rate among the best monitored waters in Florence County. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.
Trophically, Morgan Lake reads as oligotrophic — nutrient-poor, clear, and ecologically more sensitive to disturbance than richer lakes. At only 10 ft deep, Morgan Lake is shallow — wind keeps the water column mixed and sediment resuspension drives phosphorus levels harder to manage. Morgan Lake is small — 44 acres alongside partial shoreline records — which makes it sensitive to even modest changes in watershed runoff or recreational pressure. Within Florence County's 39 graded lakes, Morgan Lake ranks 23 — below the local median, though not at the bottom.
No invasive species are currently listed at Morgan Lake — the lake remains off the Wisconsin infested-waters roster. Bass fishing is part of the appeal: the species list runs to 1, anchored by largemouth and/or smallmouth bass. A documented public access point at Morgan Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. 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 2023-08-22. Grade methodology: LakeGrade methodology.
Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
Crystal clear, you can see 16.6 ft down. Phosphorus level: 13 µg/L. Trophic State Index: 39.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 16.6 ft | A |
| Phosphorus | 13 µg/L | A |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 39 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 10 ft |
| Surface Area | 44 acres |
| Public Access | Yes |
Fish Species
Click a species to see all Wisconsin and Minnesota lakes where it is found.
→ Best fishing times for Morgan Lake (14-day solunar calendar)
→ Is it safe to eat fish from Morgan Lake? (mercury & PFAS guide)
→ Morgan Lake fishing regulations (limits, seasons, special rules)
Water Quality Trend: ↓ Declining
Based on 3 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -1.95 m/yr | 2 |
Recreation & Access
Location
County Ranking
Ranked #23 of 39 lakes in Florence County
Nearby Lakes in Florence County
More Wisconsin Lake Rankings
Other Grade A Lakes in Wisconsin
Waukesha County · Clarity: 14.6 ft
Waukesha County · Clarity: 13.8 ft
Walworth County · Clarity: 19 ft
Washington County · Clarity: 12 ft
Kenosha County · Clarity: 10.1 ft
Washington County · Clarity: 12.5 ft
Oligotrophic Lakes in Wisconsin
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. 2 stations on file (most recent sample 2016).
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: 2023-08-22
Monitoring stations: 1