Minnesota DNR fisheries surveys · latest June 23, 2025
Mcmahon Lake FishingFWater-quality grade F
Minnesota DNR surveys at Mcmahon Lake average 10.64 northern pike per unit of sampling effort (CPUE) across 9 surveys. The most recent is a Standard Survey dated June 23, 2025. Length samples in the latest survey that recorded them ran 15–35 inches. In Scott County, Minnesota, Mcmahon Lake carries an overall water-quality grade of F. Water clarity averages 2.3 feet of visibility, and there is one public boat landing. The survey figures on this page are Minnesota DNR's own; the water-quality grade comes from EPA Water Quality Portal samples. Neither is a forecast of today's bite.
Species recorded at Mcmahon Lake
9 species on the Minnesota DNR list for this lake. A species on the list has been recorded here; it does not mean it is catchable today or in every part of the lake.
Stocking at Mcmahon Lake
Minnesota DNR publishes a stocking history for this lake — which species went in, how many, and in which years. Read the years: a lake stocked in one year is not necessarily stocked in the next.
Getting on the water
1 public boat landing is recorded on Mcmahon Lake. Minnesota DNR lists the public access sites, including ramp type and parking, in the documents below.
Survey results in full
Minnesota DNR surveys at Mcmahon Lake average 10.64 northern pike per unit of sampling effort (CPUE) across 9 surveys. The most recent is a Standard Survey dated June 23, 2025. Length samples in the latest survey that recorded them ran 15–35 inches.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Mcmahon Lake F from EPA Water Quality Portal chemistry, and the water-quality trend over 3 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
9 surveys on file from MN DNR Fisheries. Most recent: 2025-06-23 (Standard Survey).
Top Species by Catch Rate
| Species | Avg catch rate (CPUE) | Avg Weight |
|---|---|---|
| Bluegill | 81.66 | 0.17 lb |
| Black Crappie | 21.58 | 0.22 lb |
| Black Bullhead | 12.49 | 1.18 lb |
| Northern Pike | 10.64 | 1.67 lb |
| Yellow Perch | 9.71 | 0.13 lb |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE means more abundant in standardized sampling. This is not a weekly bite report.
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.
Bluegill
Black Crappie
Black Bullhead
Northern Pike
From the 2025-06-23 survey
McMahon is a 187-acre (158 littoral acres) lake with a maximum depth of 14 feet. McMahon is located south of the City of Prior Lake in southeast Scott County. McMahon is primarily managed for Bluegill and Largemouth but includes catchable populations of Black Crappie, Northern Pike, and Walleye. Public water access…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Mcmahon Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — McMahonFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — McMahonFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — McMahonPublic Water Access Sites · MN DNR LakeFinder
Common questions
What fish are in Mcmahon Lake?
Minnesota DNR surveys at Mcmahon Lake average 10.64 northern pike per unit of sampling effort (CPUE) across 9 surveys. The most recent is a Standard Survey dated June 23, 2025. Length samples in the latest survey that recorded them ran 15–35 inches. Minnesota DNR lists 9 species for the lake in total. Those are survey results, not a catch report: a net set on one date measures what was in that net.
When was Mcmahon Lake last surveyed?
The most recent fisheries survey on file for Mcmahon Lake is dated June 23, 2025. Survey intervals vary by lake and by species; a gap of several years between surveys is normal and does not mean the record is missing.
Is Mcmahon Lake stocked?
Minnesota DNR publishes a stocking history for Mcmahon Lake. It records which species were released, in what numbers and in which years — the source documents are linked further down this page. A lake can be stocked in some years and not others, so read the years rather than assuming an annual release.
Does the water-quality grade tell me how Mcmahon Lake fishes?
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Mcmahon Lake F from EPA Water Quality Portal chemistry, and the water-quality trend over 3 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
Before you eat what you catch
A water-quality grade is not a consumption advisory. Mercury and PCB advice for Minnesota waters comes from MDH, and it is issued per species and per size class — a lake can grade well and still carry a meal limit on larger predator fish.
Where to stay near Mcmahon Lake
Top-rated places to stay near Mcmahon Lake
Planning a trip to Mcmahon Lake?
Get lake water-quality report cards plus the best cabin & lodging deals near Mcmahon Lake — straight to your inbox. No spam, unsubscribe anytime.