Devil Lake

Where Devil Lake is

Devil Lake lies in the County of Frontenac, within the Township of South Frontenac.

How deep is Devil Lake?

The deepest mapped contour on Devil Lake is 42.7 meters, and the water within that boundary descends even farther. Ontario’s bathymetry record holds 68 depth contours for Devil 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.

Devil Lake has 8 Lake Partner monitoring sites. Eight have reported phosphorus for the three or more years the province requires before a status is assigned. Six of those sites are classified oligotrophic and one mesotrophic and one eutrophic.

The longest record is held by site 1170/2 at South of Buce Bay,E endBuceBay, with phosphorus sampled several times a year between spring and fall over 21 years to 2025. Its long-term mean phosphorus concentration is 7.59 micrograms per litre, within the oligotrophic band, which extends to 10.

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 168 clarity readings at site 1170/2 give a median Secchi depth of 6.6 meters.

Median Secchi depth by year at site 1170/2

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

Devil Lake Weather

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

Devil Lake weather

Water temperature

No provincial monitoring station records water temperature on Devil Lake. The LastLake model computes the temperature of its surface water for each day from the daily mean air temperature at Environment Canada’s Centreville climate station, 41 kilometers from the lake, or the next nearest station when its record is incomplete, and from the lake’s area of 1,058 hectares and its mean depth. The province’s records give no mean depth for Devil Lake; the model uses 11.6 meters, estimated from the lake’s depth contours.

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 Devil Lake carries the model’s figures for the past weeks and the coming week.

See also Lake Water Temperature in Ontario

Fish in Devil Lake

Ontario’s aquatic resource records name 9 fish species in Devil Lake. The province’s other records for the lake name two further species, lake whitefish and walleye. They appear in the records below.

Popular species in the province’s records

• Lake Trouttrout and whitefish
• Lake Whitefishtrout and whitefish
• Ciscotrout and whitefish
• Northern Pikepike
• Smallmouth Basssunfish
• Largemouth Basssunfish
• Rock Basssunfish
• Pumpkinseedsunfish
• Bluegillsunfish
• Brown Bullheadcatfish

Spawning areas

Ontario maps 26 fish spawning records within the Devil Lake outline, for five different species, and all of them are mapped below.

By number of records

By area mapped

• Lake Trout21 areas1.4 ha
• Northern Pike2 areas0.2 ha
• Sunfish family1 area600 m²
• Lake Whitefish1 area500 m²
• Smallmouth Bass1 area500 m²

The federal Fisheries Act prohibits the harmful alteration, disruption or destruction of fish habitat without an authorization, so a dock, dredging, infill or shoreline work at a mapped spawning area is reviewed on that basis.

Stocking history

Ontario’s stocking records for Devil Lake run from 1946 to 1991 and hold 47 releases. Walleye account for most of the fish: 650,000 released in three of the years between 1947 and 1949. The last recorded release was 2,803 lake trout yearlings in 1991.

The province’s record of stocking for recreational fishing, kept from 2016, lists no release into Devil Lake.

Eating the fish

The 2026 Guide to Eating Ontario Fish carries consumption advice for seven species taken from Devil Lake, tested for contaminants at a sampling location in Bedford Twp., Frontenac 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 18

Devil Lake lies in Fisheries Management Zone 18. Ontario sets its fishing seasons and catch limits by zone.

Fisheries management zones around Devil Lake

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

Devil Lake Ice Fishing

An ice hut on Devil Lake must be removed by March 15. 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). Devil Lake lies within FMZ 18.

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 18 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 Devil 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

Devil Lake contains 51 islands in the Ontario Hydro Network’s outline, one of them over 10 hectares and eighteen under a tenth of a hectare.

Official names

Ontario’s geographic names register lists 11 official names on the water and its islands: 7 islands, three bays and one point on an island.

Bays 3

• Buce Bay
• Hardwood Bay
• Parkers Bay

Nearby lakes

• Desert Lake11 km away
• Newboro Lake12 km away
• Bobs Lake14 km away
• Loughborough Lake14 km away

All lakes

Questions about Devil Lake

• How deep is Devil Lake?

  Its deepest charted contour is 42.7 meters, and the water within it is deeper.

• How big is Devil Lake?

  Its surface covers 10.6 square kilometers and it holds 51 islands. Of its 82 kilometers of shoreline, 60 kilometers is the mainland shore and 22 kilometers is the shore of the islands.

• What fish are in Devil Lake?

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