Muskrat Lake

Where Muskrat Lake is

Muskrat Lake lies in the County of Renfrew, within the Township of Whitewater Region.

How deep is Muskrat Lake?

The deepest mapped contour on Muskrat Lake is 64.0 meters, and the water within that boundary descends even farther. Ontario’s bathymetry record holds 12 depth contours for Muskrat Lake.

See also Ontario's Largest and Deepest Lakes

Surveyed Depths

Ontario has surveyed the depths of several thousand of its lakes over more than half a century. Later surveys were conducted by boat with satellite positioning and produced hundreds of thousands of soundings per lake. Earlier surveys were charted by running transects across the water and drawing depth contours by hand.

Water quality

Ontario’s Lake Partner Program is a volunteer monitoring network. Participants collect water samples for phosphorus analysis and measure water clarity through the summer with a Secchi disk. Most sites are sampled for phosphorus once a year, in spring, and some several times a year between spring and fall. Phosphorus in many lakes rises through the summer, so the two kinds of average are measured on different bases.

Phosphorus is the nutrient that controls how much algae a lake can grow. A lake with little phosphorus stays clear and supports cold-water fish such as lake trout. As phosphorus rises, algae increase, the water clouds, and oxygen in the deep water falls as the algae decay. The province classifies each monitoring site by its average phosphorus:

• Oligotrophic, below 10 micrograms per litre: clear water and low algae.
• Mesotrophic, from 10 to 20: moderately productive water, with more algae and weed growth than an oligotrophic lake but rarely a bloom.
• Eutrophic, above 20: nutrient-rich water, prone to algal blooms and low oxygen at depth.

Muskrat Lake has 6 Lake Partner monitoring sites. Three have reported phosphorus for the three or more years the province requires before a status is assigned. All are classified eutrophic.

The longest record is held by site 3401/2 at S end Near Cobden, with phosphorus sampled several times a year between spring and fall over 5 years to 2010. Its long-term mean phosphorus concentration is 31.63 micrograms per litre, within the eutrophic band, which begins at 20.

A Secchi disk is a white or black-and-white plate lowered on a marked line until it disappears from view. The depth at which it vanishes is the Secchi depth, a direct measure of water clarity. Clearer water gives a deeper reading.

The 22 clarity readings at site 3401/2 give a median Secchi depth of 1.5 meters.

Median Secchi depth by year at site 3401/2

See also Lake Water Quality and Blue-Green Algae in Ontario

Muskrat Lake Weather

The weather page for Muskrat Lake carries the forecast over the water, wave heights across the lake, and the modelled water temperature.

Muskrat Lake weather

Water temperature

Ontario’s aquatic resource records class Muskrat Lake as a cold-water lake, with a mean depth of 17.9 meters against its maximum of 64.

A deep lake separates into layers through the summer. Sunlight and wind warm and mix the upper few meters, and beneath a band of rapid cooling, the thermocline, the water stays cold through the whole season. A mean depth of 17.9 meters places most of Muskrat Lake’s volume in that cold layer, which is the condition lake trout and lake whitefish require.

No provincial monitoring station records water temperature on Muskrat Lake. The LastLake model computes the temperature of its surface water for each day from the daily mean air temperature at Environment Canada’s Pembroke Climate climate station, 33 kilometers from the lake, or the next nearest station when its record is incomplete, and from the lake’s area of 1,219 hectares and its mean depth of 17.9 meters.

Each day’s figure carries the model’s typical error for that month on lakes of the same size. The figure in the chart below is the temperature near the surface, away from the shoreline. Bays, shallows and water deeper below the surface differ in temperature. Temperature is not measured when ice covers the lake. The weather page for Muskrat Lake carries the model’s figures for the past weeks and the coming week.

See also Lake Water Temperature in Ontario

Fish in Muskrat Lake

Ontario’s aquatic resource records name 33 fish species in Muskrat Lake. The province’s other records for the lake name two further species, brook trout and lake whitefish. They appear in the records below.

Popular species in the province’s records

• Lake Trouttrout and whitefish
• Northern Pikepike
• Muskellungepike
• Walleyeperch
• Yellow Perchperch
• Smallmouth Basssunfish
• Largemouth Basssunfish
• Black Crappiesunfish
• Rock Basssunfish
• Pumpkinseedsunfish
• Bluegillsunfish
• Brown Bullheadcatfish
• Channel Catfishcatfish
• Lake Sturgeonother

Stocking history

Ontario’s stocking records for Muskrat Lake run from 1946 to 2015 and hold 63 releases. Walleye account for most of the fish: 7,850,000 released in nine of the years between 1946 and 1972. The last recorded release was 7,000 lake trout yearlings in 2015.

Eating the fish

The 2026 Guide to Eating Ontario Fish carries consumption advice for eight species taken from Muskrat Lake, tested for contaminants at a sampling location in Westmeath & Ross Twps., Renfrew Co. Each figure below is the most meals a month the guide advises for a fish of that length. Where mercury sets the advice, the figure falls as the fish gets longer, because mercury accumulates over a fish’s life. Where the guide has no result yet for certain contaminants at a location, it sets a precautionary limit of 16 meals a month. A zero means the guide advises no meals of that fish at that size.

General population: adultsSensitive population: children under fifteen, women who are or may become pregnant

Fisheries Management Zone 15

Muskrat Lake lies in Fisheries Management Zone 15. Ontario sets its fishing seasons and catch limits by zone. The province describes it as a zone of many natural lake trout and brook trout lakes, with a well-developed road network and moderate angling effort.

Fisheries management zones around Muskrat Lake

See also Fishing Seasons in Ontario, Zone by Zone and Fish Stocking in Ontario Lakes

Muskrat Lake Ice Fishing

An ice hut on Muskrat Lake must be removed by March 31. The province sets dates for ice hut removal as a safety measure to ensure huts are removed before thawing occurs. One date applies to an entire fisheries management zone (FMZ). Muskrat Lake lies within FMZ 15.

An ice hut must also be removed before the ice breaks up, whether or not that date has passed. The deadline clears huts from the ice ahead of the thaw and does not close the fishing season.

Registration is required in FMZ 15 for an ice hut built of anything other than fabric, and for a fabric tent covering seven square meters or more. Registration is free, and the number is displayed on the outside of the hut.

Ice conditions

No public record reports the thickness or the condition of the ice on Muskrat Lake on any given day. Ontario publishes ice safety guidance for anyone going out on the ice, at ontario.ca.

See also Lake Ice in Ontario and When the Lakes Will Freeze This Winter

Islands and names

Muskrat Lake contains one island in the Ontario Hydro Network’s outline, of 0.1 hectare, none of them named in the province’s register.

Official names

Ontario’s geographic names register lists 4 official names on the water and its islands: three bays and one river. A further 1 named point stands on the mainland shore.

Bays 3

• Boyds Bay
• Lily Bay
• McNaughton Bay

Points on the shore 1

• Coffeys Point

Nearby lakes

• Mink Lake16 km away
• Lake Doré18 km away
• Constant Lake31 km away
• Lake Clear34 km away

All lakes

Questions about Muskrat Lake

• How deep is Muskrat Lake?

  Its deepest charted contour is 64 meters, and the water within it is deeper.

• How big is Muskrat Lake?

  Its surface covers 12.2 square kilometers, with 36 kilometers of shoreline and 1 island.

• What fish are in Muskrat Lake?

  Ontario’s aquatic resource records name 33 species, among them lake trout, walleye, smallmouth bass, largemouth bass, northern pike and muskellunge. The lake’s spawning, consumption and stocking records also name brook trout and lake whitefish.

• Is the water clear?

  All three monitoring sites with a phosphorus status are classified eutrophic, the most nutrient-rich of the province’s three bands.