Martha Lake
Wright County, MinnesotaEutrophic
Martha Lake pulls a D on the LakeGrade rubric — phosphorus loading and limited clarity hold it below the Minnesota average. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.
Eutrophic conditions are the baseline here: clarity drops noticeably in late summer, and dissolved oxygen near the bottom can become a concern. Martha Lake reaches 22 ft at its deepest point — typical for Minnesota mid-sized lakes, with seasonal stratification but limited cold-water refuge. Martha Lake covers 102 acres alongside 1.9 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Martha Lake sits at rank 47 of 64 in Wright County, in the lower half of the local distribution.
Martha Lake has no invasive species recorded in Minnesota state databases as of 2024, though prevention practices still apply at all access points. The fishery includes walleye alongside the lake's other 9 documented species — a notable draw for Minnesota anglers. Public access is available — the lake is on the Minnesota PCA public-access list. 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, Minnesota DNR LakeFinder, last sampled 2024-10-02. Grade methodology: LakeGrade methodology.
Swimming Safety
Swimming not recommended, poor water quality with high algae risk
Water Quality Grade: D, Poor
Very murky, less than 3 ft of visibility. Phosphorus level: 75 µg/L. Trophic State Index: 64.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3 ft | F |
| Phosphorus | 75 µg/L | D |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 64 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 22 ft |
| Average Depth | 7.9 ft |
| Surface Area | 102.45 acres |
| Shoreline Length | 1.9 mi |
| Littoral Zone | 70% |
| Public Access | Yes |
Fish Species
Click a species to see all Minnesota and Wisconsin lakes where it is found.
→ Best fishing times for Martha Lake (14-day solunar calendar)
→ Is it safe to eat fish from Martha Lake? (mercury & PFAS guide)
→ Martha Lake fishing regulations (limits, seasons, special rules)
Water Quality Trend: ↓ Declining
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.684 m/yr | 5 |
| Phosphorus | ↓ Declining | +9.8 µg/L/yr | 5 |
Ice Season
Historical ice data from Minnesota DNR (14 observations).
Estimated open water season: 235 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2016-03-13 (2016) | 2008-04-21 (2008) |
| Ice-In | 1991-11-04 (1991) | 1998-12-20 (1998) |
Most recent ice-out: 2016-03-13
Location
County Ranking
Ranked #47 of 64 lakes in Wright County
Nearby Lakes in Wright County
More Minnesota Lake Rankings
State Parks Near Martha Lake
Other Grade D Lakes in Minnesota
Eutrophic Lakes in Minnesota
DNR Fisheries Survey Summary
6 surveys on file from MN DNR Fisheries. Most recent: 2022-06-13 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Black Bullhead | 184.85 | 0.41 lb |
| Bluegill | 34.85 | 0.18 lb |
| Black Crappie | 32.36 | 0.19 lb |
| Largemouth Bass | 29.15 | 0.92 lb |
| Pumpkinseed | 22.74 | 0.13 lb |
| Hybrid Sunfish | 14.30 | 0.21 lb |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
Length Distributions
Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.
Black Bullhead
Bluegill
Black Crappie
Largemouth Bass
From the 2022-06-13 survey
Lake Martha is a small 97-acre lake located two miles southwest of Hanover in Wright County. Martha has a maximum depth of 25 feet and an average water clarity of six feet. A state-owned public access is located along the south shore and offers parking for two to three vehicle/trailer combos. A standard survey was…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Martha Lake. 3 reports on file.
- —Fisheries Lake Survey — MarthaFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Martha (2024)Aquatic Plant Report · MN DNR LakeFinder
- —Public Water Access Sites — MarthaPublic Water Access Sites · MN DNR LakeFinder
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Lake details from Minnesota DNR LakeFinder
Ice data from Minnesota DNR Climate
Most recent sample: 2024-10-02
Monitoring stations: 1