Leeds and Grenville, Ontario
Big Rideau Lake
One hundred and eighty-eight islands and a charted depth of 91.4 meters, from the province's 1972 survey, inside 228 kilometers of shoreline. Ontario's aquatic resource record lists 47 species in the lake.
- Surface
- 45.9 km²
- Shoreline
- 228 km160 mainland + 68 islands
- Islands
- 188
- Charted depth
- 91.4 m
- Depth contours
- 574
All figures are derived from Ontario’s survey records.
Where Big Rideau Lake is
Big Rideau Lake lies in the County of Lanark and the United Counties of Leeds and Grenville, with shoreline in the Township of Tay Valley, the Township of Rideau Lakes and the Township of Drummond/North Elmsley.
How deep is Big Rideau Lake?
The deepest mapped contour on Big Rideau Lake is 91.4 meters, and the water within that boundary descends even farther. Ontario’s bathymetry record holds 574 depth contours for Big Rideau Lake.
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 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.
Big Rideau Lake has 18 Lake Partner monitoring sites. Ten 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 four mesotrophic.
| Site | Location | Years | Last sampled | Classification |
|---|---|---|---|---|
| 4624/4 | Tower Island-BRLA13 | 11 | 2016 | oligotrophic |
| 4624/5 | Trout Island-RVCA | 10 | 2016 | oligotrophic |
| 4624/7 | Star Island | 9 | 2016 | oligotrophic |
| 4624/18 | O'Mearas Bay | 6 | 2025 | mesotrophic |
| 4624/3 | Tar Island-BRLA32 | 6 | 2016 | oligotrophic |
| 4624/11 | Hogg's Bay | 5 | 2016 | mesotrophic |
| 4624/2 | Briton Bay-BRLA01 | 5 | 2016 | mesotrophic |
| 4624/10 | Big Rideau | 4 | 2016 | oligotrophic |
| 4624/6 | Narrows Lock-BRLA56 | 4 | 2016 | oligotrophic |
| 4624/1 | McLeans Bay-BRLA45 | 3 | 2015 | mesotrophic |
The longest record is held by site 4624/4 at Tower Island-BRLA13, sampled over 11 springs to 2016. Its long-term mean phosphorus concentration is 9.03 micrograms per litre, within the oligotrophic band, which extends to 10. The site’s 18 clarity readings give a median Secchi depth of 6.5 meters.
Fish in Big Rideau Lake
Ontario’s aquatic resource records name 47 fish species in Big Rideau Lake. The province classes the lake as cold water. The record took effect on 29 November 2018, and it compiles what field biologists had reported by then.
Seventeen of the 47 species in the province’s records
Lake Trouttrout and whitefish
Brook Trouttrout and whitefish
Lake Whitefishtrout and whitefish
Ciscotrout and whitefish
Northern Pikepike
Muskellungepike
Walleyeperch
Yellow Perchperch
Smallmouth Basssunfish
Largemouth Basssunfish
Black Crappiesunfish
White Crappiesunfish
Rock Basssunfish
Pumpkinseedsunfish
Bluegillsunfish
Burbotcod
Brown Bullheadcatfish
| Family | Species |
|---|---|
| Perch | iowa darter, johnny darter x tesselated darter, tessellated darter |
| Catfish | yellow bullhead |
| Sucker | white sucker |
| Smelt | rainbow smelt |
| Minnow | blackchin shiner, blacknose shiner, bluntnose minnow, carps and minnows, common shiner, emerald shiner, fathead minnow, golden shiner, lake chub, sand shiner, spottail shiner |
| Sculpin | slimy sculpin, spoonhead sculpin |
| Stickleback | ninespine stickleback |
| Herring | alewife, gizzard shad |
| Eel | american eel |
| Killifish | banded killifish |
| Mudminnow | central mudminnow |
| Silverside | brook silverside |
| Other | bridle shiner, fallfish, moxostoma sp., notropis sp. |
Spawning areas
Ontario maps 230 fish spawning records within the Big Rideau Lake outline, for eleven species. Eighteen are nests or records of under 100 square meters each, and the other 212 are mapped areas. Nineteen of the areas are one outline mapped for largemouth bass and northern pike alike, and 23 more are filed under more than one species. An outline filed for more than one species is drawn once, striped in each of their colours.
By number of records
By area mapped
- Smallmouth Bass58 areas92.1 ha
- Lake Trout40 areas14.8 ha
- Lake Whitefish39 areas19.0 ha
- Largemouth Bass38 areas32.4 ha
- Northern Pike22 areas17.9 ha
- Yellow Perch9 areas19.8 ha
- Yellow Perch nursery4 records200 m²
- Blue Gill nursery4 records300 m²
- Emerald Shiner nursery4 records300 m²
- Walleye3 areas0.4 ha
- Pumpkinseed nursery2 nests100 m²
- Rock Bass nursery2 nests100 m²
- Northern Pike nursery2 records200 m²
- Pumpkinseed1 area0.9 ha
- Smallmouth Bass nursery1 area0.5 ha
- Largemouth Bass nursery1 area0.5 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 Big Rideau Lake run from 1930 to 2009 and hold 167 releases. Walleye account for most of the fish: 10,620,000 released in ten of the years between 1936 and 1977. The last recorded release was 11,132 lake trout yearlings in 2009.
| Species | Years | Years with a release | Fish released |
|---|---|---|---|
| Walleye | 1936 to 1977 | 10 | 10,620,000 |
| Lake Trout | 1936 to 2009 | 59 | 1,105,047 |
| Smallmouth Bass | 1930 to 1978 | 34 | 215,550 |
| Largemouth Bass | 1947 to 1978 | 15 | 123,840 |
The province’s current stocking programme, recorded from 2016, lists no release into Big Rideau Lake.
Fisheries Management Zone 18
Big Rideau Lake lies in Fisheries Management Zone 18. Ontario sets its fishing seasons and catch limits by zone.
| Species | Open season | Sport licence | Conservation licence |
|---|---|---|---|
| Brook Trout | Open all year | 5 | 2 |
| Brown Trout | Open all year | 5 | 2 |
| Channel Catfish | Open all year | 12 | 6 |
| Crappie | Open all year | 30 | 10 |
| Lake Trout | 4th Sat. in May – Sept. 8 | 2 | 1 |
| Lake Whitefish | Open all year | 12 | 6 |
| Largemouth and Smallmouth Bass or any combination | 3rd Sat. in June – Dec. 15 | 6 | 2 |
| Muskellunge | 1st Sat. in June – Dec. 15 | 1, must be greater than 91 cm (36 in.) | 0 |
| Northern Pike | Jan. 1 – Mar. 31 & 2nd Sat. in May – Dec. 31 | 6 | 2 |
| Pacific Salmon | Open all year | 5 | 2 |
| Rainbow Trout | Open all year | 5 | 2 |
| Splake | Open all year | 5 | 2 |
| Sunfish | Open all year | 300, only 30 may be greater than 18 cm (7.1 in.) | 15 |
| Walleye and Sauger or any combination | Jan. 1 – Mar. 1 & 2nd Sat. in May – Dec. 31 | 4, must be between 40 – 50 cm (15.7 – 19.7 in.) | 2, must be between 40 – 50 cm (15.7 – 19.7 in.) |
| Yellow Perch | Open all year | 50 | 25 |
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 Big Rideau Lake.
| Where | Closed |
|---|---|
| Big Rideau Lake (The Bog and Long Island) – Bastard and Burgess Twps | Closed all year |
| Big Rideau Lake (The Bog and Long Island) – Bastard and Burgess Twps | Closed all year |
Big Rideau Lake Ice Fishing
An ice hut on Big Rideau Lake must be removed by March 15. Big Rideau Lake lies in fisheries management zone 18, 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 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 Big Rideau Lake on any given day. Ontario publishes ice safety guidance for anyone going out on the ice, at ontario.ca.
Islands and names
Big Rideau Lake contains 188 islands in the Ontario Hydro Network’s outline, four of them over 10 hectares and 80 under a tenth of a hectare. Thirteen of them lie inside wetlands mapped in the province’s Wetland With Significance dataset.
| Island | Hectares | |
|---|---|---|
| 1 | Colonel By Island | 77.1 |
| 2 | Big Island | 30.4 |
| 3 | Tar Island | 19.2 |
| 4 | MacDonalds Island | 17.6 |
| 5 | Sand Island | 8.2 |
| 6 | McVeetys Island | 5.5 |
| 7 | Ferguson Island | 5.0 |
| 8 | Grindstone Island | 4.9 |
| 9 | unnamed | 4.8 |
| 10 | unnamed | 4.0 |
Official names
Ontario’s geographic names register lists 118 official names on the water and its islands: 66 islands, 24 bays, eight shoals, nine rocks, one narrows and six points on islands. A further 22 named points stand on the mainland shore. The register records the origin of two names.
Bays 24
- Bass Bay
- Beaver Bay
- Bellows Bay
- Bests Bay
- Briton Bay
- Coutts Bay
- Davidsons Bay
- Green Bay
- Hawse Bay
- Hoggs Bay
- Houghton Bay
- Hudson Bay
- Jacklins Bay
- MacDonalds Bay
- McLeans Bay
- McVeetys Bay
- Mill Bay
- Minnow Bay
- Murphys Bay
- Narrows Bay
- Nobles Bay
- O'Mearas Bay
- Sheldons Bay
- Sherwoods Bay
Shoals and rocks 17
- Agnes Rock
- Big Island Shoal
- Cow Island Shoal
- Cruiser Cracker
- Elswood Rock
- Gull Shoal
- Howell Rock
- Loretta Rock
- Maggie May Shoal
- Peerless Shoal
- Pumper Rock
- Rideau King Rock
- Rideau Queen Rock
- Sheep Island Shoal
- Swan Rock
- Tower Shoal
- Turtle Shoal
Harbours, cuts and narrows 1
- Rocky Narrows
Points on the shore 22
- Amis Point
- Bests Point
- Black Ance Point
- Cedar Point
- Davidsons Point
- Donovans Point
- Frost Point
- Herman Point
- Klautz Point
- MacDonalds Point
- McNamees Point
- McVeetys Point
- Murphys Point
- Pethern Point
- Pine Point
- Rams Point
- Rocky Point
- Scotch Point
- Sheldons Point
- Sherwoods Point
- Southams Point
- Tracys Point
Nearby lakes
- Newboro Lake13 km away
- Christie Lake16 km away
- Sand Lake19 km away
- Upper Beverley Lake19 km away
Questions about Big Rideau Lake
- How deep is Big Rideau Lake?
Its deepest charted contour is 91.4 meters, and the water within it is deeper.
- How big is Big Rideau Lake?
Its surface covers 45.9 square kilometers and it holds 188 islands. Of its 228 kilometers of shoreline, 160 kilometers is the mainland shore and 68 kilometers is the shore of the islands.
- What fish are in Big Rideau Lake?
Ontario’s aquatic resource records name 47 species, among them lake trout, walleye, smallmouth bass, largemouth bass, northern pike and muskellunge.
A print of Big Rideau Lake
Big Rideau Lake has not yet been drawn as a print. The lakes drawn so far are on the lake maps page, and a print of Big Rideau Lake can be requested by email; whether it can be drawn is confirmed before any payment.
Ask about a Big Rideau Lake printLooking at a property on Big Rideau Lake?
Depth and water quality are two records out of many. Our Rural & Cottage Buyer’s Report gathers what the public record holds about one specific address: shore road allowance, road access, wells, flood mapping, Crown land, wetlands and more, read and checked by a person before it is sent.
What these figures do and do not say
- Depth
- A depth reading is the distance from the water surface on the day of survey to the lake bottom. Lake levels vary through the season and between years. The depth figure above is the deepest contour charted and is a minimum; the depth within it was not recorded. The figures for Big Rideau Lake are read from the province’s bathymetry records within the Ontario Hydro Network’s outline of the lake: the deepest figure is the deepest record inside that outline, and the count is every record inside it.
- Shoreline and surface
- The shoreline figure is the length of the mainland shore and of every island shore added together, measured on the Ontario Hydro Network’s outline of the lake. The surface figure is the area of water inside that outline, less the area of its islands. The provincial outline is mapped to within a few meters of the shore, and a shoreline measured from a coarser map comes out shorter, which is why a figure published elsewhere is often lower.
- Survey coverage
- Not every survey covered every arm of a lake, and the province’s index does not always record where a survey ended.
- Water quality
- Each figure belongs to a single monitoring site and not to the lake as a whole. A bay receiving a creek can read differently from open water half a kilometer away. Sites are matched to Big Rideau Lake by name in the province’s records.
- Nearby lakes
- Distances are measured between lake centres.
- Islands and names
- Islands are counted and measured on the Ontario Hydro Network outline; names are the register’s, placed by its own coordinate. The register names islands the outline draws as part of a larger one, and the outline holds islands the register has not named, so the two counts differ. The outline carries some lakes across marsh, so a gap in the marsh is drawn as land, and every such gap is included in the island count. Where the register has not named one and it lies mostly inside a wetland in the province’s Wetland With Significance dataset, the page names the wetland and the table of largest islands leaves it out. Wetland boundaries are mapped at their own scale and can cover a small island whole.
- Depth contours
- Each contour is drawn where the survey placed it, at the survey’s own positional accuracy. The survey carries its own shoreline, which differs from the Ontario Hydro Network’s outline, so a contour near the shore can run to or past the outline. Such a stretch is drawn along the outline, as a drawing convention, and is not the survey’s line there. The contour count in the stat band is the province’s, and it includes the survey’s own shoreline contour, one ring around the mainland and one around each charted island, which the map leaves off; the map’s small print gives the split.
- Location
- Municipal boundaries are read from the province’s records as published and can lag a boundary change.
- Fish
- Ontario’s fish records are compilations of existing knowledge from field biologists and do not represent exhaustive inventories. A species that is not listed was not ruled out. The species list carries one date for the whole record and none for any species.
- Spawning areas
- A spawning area is drawn where the province mapped it, at the province’s stated accuracy, and the record says nothing about how many fish use it in a given year. A nest record is one nest seen on one day; a count of nests is not a count of fish, and a count of records is not a comparison between species. Whether a given piece of work needs an authorization is a determination made by Fisheries and Oceans Canada on the work itself.
- Stocking
- A stocking record is a release on a date. It says nothing about how many fish survived or about the population in the lake today.
- Fishing rules
- Seasons and limits are the zone’s, for the year of the dataset the page was built from, and a licence’s own conditions and any waterbody exception apply over them. The province’s regulations summary is the authority.
- Ice hut rules
- Removal dates and registration rules are set by fisheries management zone and change from time to time. The dates here were read from the province in September 2026. The province’s own fishing regulations are the authority.
Where these figures come from
- Depth, shoreline, islands and named places: Ontario Ministry of Natural Resources bathymetry and the Ontario Hydro Network, © King’s Printer for Ontario, Open Government Licence – Ontario.
- Phosphorus and water clarity: Ontario Lake Partner Program, Ministry of the Environment, Conservation and Parks, Open Government Licence – Ontario. Extract built 2026-08-09.
- Aerial photography: Geospatial Ontario imagery, Open Government Licence – Ontario, released collections only.
- Official names: Geographic Names Ontario, Ministry of Natural Resources, Open Government Licence – Ontario. Marinas: Overture Maps Foundation places data, CDLA-Permissive 2.0.
- Lake outline and municipal boundaries: Ontario Hydro Network and Ontario municipal boundary records, Ministry of Natural Resources, Open Government Licence – Ontario.
- Fish species and thermal regime: Ontario Aquatic Resource Area records. Spawning areas: Ontario Fish Activity Area records. Both Ministry of Natural Resources, Open Government Licence – Ontario.
- Stocking: Historical Fish Stocking Data and Fish Stocking Data for Recreational Purposes, Ministry of Natural Resources, Open Government Licence – Ontario.
- Seasons and limits: Ontario recreational fishing regulations data, Ministry of Natural Resources, Open Government Licence – Ontario.
- Fish plates: Duane Raver, U.S. Fish and Wildlife Service; Ellen Edmonson and Hugh Chrisp, New York State Conservation Department; Timothy Knepp, U.S. Fish and Wildlife Service; U.S. Fish and Wildlife Service. All public domain.
- Ice hut removal dates and registration: Ontario fishing regulations, read September 2026.