Chemong Lake

Where Chemong Lake is

Chemong Lake lies in the County of Peterborough, with shoreline in the Township of Selwyn and the City of Kawartha Lakes.

How deep is Chemong Lake?

The deepest mapped contour on Chemong Lake is 6.7 meters, and the water within that boundary descends even farther. The chart is drawn from 74 depth contours recorded during Ontario’s 1967 survey.

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.

Chemong Lake Aerial Photography

Ontario photographs the province from the air on a rolling schedule.

The photograph below is from the SCOOP2023 collection.

Water quality

Ontario’s Lake Partner Program is a volunteer monitoring network. Participants collect a water sample each spring for phosphorus analysis and measure water clarity through the summer with a Secchi disk.

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 spring phosphorus. Below 10 micrograms per litre is oligotrophic: clear water and low algae. From 10 to 20 is mesotrophic: moderately productive water, with more algae and weed growth than an oligotrophic lake but rarely a bloom. Above 20 is eutrophic: nutrient-rich water, prone to algal blooms and low oxygen at depth.

A Secchi disk is a 20 centimeter 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.

Chemong Lake has 7 Lake Partner monitoring sites. Five have reported phosphorus for the three or more years the province requires before a status is assigned. Three of those sites are classified mesotrophic and two eutrophic.

The longest record is held by site 6951/9 at S. of Causeway, sampled over 14 springs to 2023. Its long-term mean phosphorus concentration is 22.6 micrograms per litre, within the eutrophic band, which begins at 20. The site’s 50 clarity readings give a median Secchi depth of 2.9 meters.

Water temperature

Ontario’s aquatic resource records class Chemong Lake as a warm-water lake, with a mean depth of 2.4 meters against its maximum of 6.7.

A lake separates into layers through the summer where it is deep enough. Sunlight and wind warm and mix the upper few meters, and beneath a band of rapid cooling, the thermocline, the water stays cold. A shallow lake mixes to the bottom instead and warms through, sooner in spring and later into autumn.

No provincial monitoring station records water temperature on Chemong Lake. The province’s longest in-water record is kept on eight research lakes near Dorset, sampled since 1976. A reading is taken at the surface, at one meter, at each meter to seven and then every two meters to the bottom, about every two weeks through the open-water season and about monthly under ice. The record holds 5,240 readings at a depth of one meter.

At one meter the eight lakes track one another closely. On a day when several were sampled, the warmest and the coolest lake differed by about one degree in every month of the year, and a 12 meter deep lake and a 37 meter deep lake read within 0.2 degrees of each other from June to October. The weather of the year, and not the lake, sets most of the width of the band below.

Satellite thermal imagery gives a surface reading on clear days: the Landsat sensors pass over Chemong Lake every eight days at a resolution of 100 meters. In the province’s record the surface reading and the one meter reading agree to within half a degree nine times in ten in summer.

The water a few meters down is colder than any figure on this chart, in every month of the year.

How depth changes the temperature

The chart below is the province’s record on Harp Lake, 37 meters deep, drawn as the median temperature at each depth for each month over 49 years. In July the water at one meter is 23 degrees, at five meters 15, at seven meters 9, and from 13 meters to the bottom under 6. By October the warm layer has deepened to seven meters and cooled to 11 degrees. In February the whole column sits between 1 and 4 degrees under the ice, coldest at the top.

A shallower lake in the same record warms sooner. Heney Lake, six meters deep, reads about 1.8 degrees warmer than Harp Lake at one meter from January to May, 0.8 degrees warmer from June to August, and the same or cooler from September.

Fish in Chemong Lake

Ontario’s aquatic resource records name 35 fish species in Chemong Lake. The province classes the lake as warm water. The record took effect on 5 October 2010, and it compiles what field biologists had reported by then.

Eleven of the 35 species in the province’s records

• Muskellungepike
• Walleyeperch
• Yellow Perchperch
• Smallmouth Basssunfish
• Largemouth Basssunfish
• Black Crappiesunfish
• Rock Basssunfish
• Pumpkinseedsunfish
• Bluegillsunfish
• Brown Bullheadcatfish
• Common Carpminnow

Spawning areas

Ontario maps 44 fish spawning records within the Chemong Lake outline, for three species, all of them mapped areas. Every record is recorded as verified and presently suitable, and none is classed as sensitive.

By number of records

By area mapped

• Smallmouth Bass25 areas64.9 ha
• Muskellunge10 areas15.0 ha
• Largemouth Bass9 areas10.4 ha

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 Chemong Lake run from 1946 to 1987 and hold 70 releases. Muskellunge account for most of the fish: 1,220,250 released in 31 of the years between 1946 and 1987. The last recorded release was 1,500 muskellunge fingerlings in 1987.

The province’s current stocking programme, recorded from 2016, lists no release into Chemong Lake.

Eating the fish

The 2025 Guide to Eating Ontario Fish carries consumption advice for ten species taken from Chemong Lake, tested for contaminants at a sampling location in Ennismore & Smith Twps., Peterborough Co. Each figure below is the most meals a month the guide advises for a fish of that length. The advice falls as the fish gets longer, because mercury accumulates over a fish’s life. 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 17

Chemong Lake lies in Fisheries Management Zone 17. Ontario sets its fishing seasons and catch limits by zone.

The figures are the number of fish an angler may catch and keep in a day and have in possession, under a sport fishing licence and under a conservation licence. The rows are the whole zone’s, and they apply to every lake in it. No waterbody exception names Chemong Lake.

Chemong Lake Ice Fishing

An ice hut on Chemong Lake must be removed by March 1. Chemong Lake lies in fisheries management zone 17, one of the twenty zones Ontario sets its fishing rules by, and one removal date applies across the whole zone.

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 zone 17 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.

When the ice goes out

The ice has been recorded leaving Chemong Lake in 110 springs between 1900 and 2017. The median date is April 16. The earliest recorded break-up is March 21 in 1983 and 2012, and the latest is May 4 in 1936 and 1972.

Across the 110 recorded springs the median date has moved by less than a day each decade.

The record was contributed by Peter J. Dillon, Ontario Ministry of the Environment to the Global Lake and River Ice Phenology Database. It holds the day the ice left and carries no date for the day it formed, so it says nothing about when Chemong Lake freezes.

Ice conditions

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

Getting on the water

Ten access marks are mapped on Chemong Lake: five boat launches, two marinas and three beaches. Six are Ontario’s own records, two are from the Overture Places dataset and two are operator entries, and the list under the map says which is which. Boat launch is the province’s class for a ramp.

Islands and names

Chemong Lake contains 33 islands in the Ontario Hydro Network’s outline, three of them over 10 hectares and ten under a tenth of a hectare. Nine of them lie inside wetlands mapped in the province’s Wetland With Significance dataset. The largest two, of 18.0 and 14.5 hectares, fall inside the Chemong Lake 25 and Chemong Lake No. 27 wetlands. Big Island, at 20 hectares, is larger than the next ten together, which cover 7.0.

Official names

Ontario’s geographic names register lists 15 official names on the water and its islands: 6 islands, six bays, one shoal, one narrows and one point on an island. A further 10 named points stand on the mainland shore.

Bays 6

• Donaghue Bay
• Fife's Bay
• Gifford Bay
• Lancaster Bay
• Telford Bay
• Tindle Bay

Shoals and rocks 1

• Curve Shoal

Harbours, cuts and narrows 1

• Chemong Narrows

Points on the shore 10

• Coppaway Point
• Gannon Point
• Hickson Point
• Lute Point
• McGuire Point
• McIllmoy Point
• O'Rielly Point
• Scollard Point
• Scotsman Point
• Spencer Point

Communities on the lake 12

• Bridgenorth
• Chemong Park
• Chemong Heights
• Youngstown
• Fife's Bay
• Stewart Heights
• Fowlers Corners
• Bethel
• Ennismore
• Connaught Shore
• Curve Lake
• Selwyn

Nearby lakes

• Buckhorn Lake9 km away
• Pigeon Lake9 km away
• Sandy Lake14 km away
• Lower Buckhorn Lake16 km away

All lakes

Questions about Chemong Lake

• How deep is Chemong Lake?

  Its deepest charted contour is 6.7 meters, and the water within it is deeper.

• How big is Chemong Lake?

  Its surface covers 24.8 square kilometers and it holds 33 islands. Of its 107 kilometers of shoreline, 89 kilometers is the mainland shore and 18 kilometers is the shore of the islands.

• What fish are in Chemong Lake?

  Ontario’s aquatic resource records name 35 species, among them walleye, smallmouth bass, largemouth bass, muskellunge, yellow perch and black crappie.

• Is there a public boat launch?

  Records mark five boat launches, two marinas and three beaches on Chemong Lake.