Brennan Lake
50.4778° N, 89.9252° W
Depth contours from the 1980 government survey. Not for navigation.
Download the depth map (SVG)Brennan Lake, Ontario. 50.4778° N, 89.9252° W
Maximum depth 20 m (1980 survey). Scale bar on the map.
Not for navigation. Depths are from government surveys and may be outdated.
borealbound.ca/lakes/on/brennan-lake/, compiled October 9, 2026
- Canadian Geographical Names Database, Natural Resources Canada. Contains information licensed under the Open Government Licence – Canada.
- HydroLAKES v1.0, Messager et al. 2016 / WWF HydroSHEDS. Licensed under CC BY 4.0.
- Census boundaries and population, 2021, Statistics Canada. Adapted from Statistics Canada. This does not constitute an endorsement by Statistics Canada.
- Fisheries Management Zones, Ontario Ministry of Natural Resources. Contains information licensed under the Open Government Licence – Ontario.
- Bathymetry lines and survey index, Ontario Ministry of Natural Resources. Contains information licensed under the Open Government Licence – Ontario.
- City page weather forecasts and alerts, Environment and Climate Change Canada. Contains data from Environment and Climate Change Canada (ECCC Data Servers End-use Licence).
Brennan Lake is 20 m deep at its deepest point, deeper than 60% of the 2,688 surveyed lakes in Ontario. It covers 24.6 km² and lies 20 km northeast of Allanwater Bridge.
- Maximum depth
- 20 msurveyed 1980
- deeper than 60% of the 2,688 surveyed lakes in Ontario
- Area
- 24.6 km²
- larger than 98% of the 18,731 lakes in Ontario
- Shoreline
- 206 km
- longer than 99% of the 18,731 lakes in Ontario
- Elevation
- 381 m
Today on the water
-0.8 °C
Observed at Armstrong, as of 3:00 a.m. EDT
calm Estimated waves, next 12 hours: up to 0.1 m. Around 4 a.m., wind from the west: the west shore is sheltered, waves build toward the east shore.
| Time | 4 a.m. | 7 a.m. | 10 a.m. | 1 p.m. | 4 p.m. | 7 p.m. | 10 p.m. | 1 a.m. |
|---|---|---|---|---|---|---|---|---|
| Wind km/h | W 10 | W 10 | var. 5 | var. 5 | SE 10 | SE 10 | SE 20 | SE 20 |
| Waves (est.) m | 0.1 | 0.1 | 0.1 | 0.1 | ||||
| Temp. °C | 0 | -1 | 3 | 9 | 10 | 9 | 7 | 6 |
| Precip. % | 20 | 20 | 20 | 20 | 40 | 40 | 40 | 40 |
Tonight: Cloudy. 30 percent chance of showers early this evening. Becoming partly cloudy near midnight. Wind northwest 20 km/h becoming light this evening. Low minus 2.
Weather: Armstrong (local forecast), as of 3:02 a.m. EDT
Sun and moon
- Civil dawn
- 7:40 a.m.
- Sunrise
- 8:12 a.m.
- Sunset
- 7:20 p.m.
- Civil dusk
- 7:52 p.m.
- Moonrise
- 7:05 a.m.
- Moonset
- 6:38 p.m.
- Moon
- Waning crescent, 1% lit
Follow this lake by email: a weekly summary of conditions.
Depth
3% of Brennan Lake is deeper than 10 m.
How to read it: the lake’s area is sorted from the shore to the deepest point. Where the curve is flat, large areas share one depth (flats and weed beds); where it drops, depth changes quickly (drop-offs).
The government depth survey from 1980 records a maximum depth of 20 m, drawn from 171 depth contours.
- Download the depth map (SVG)Printing this page gives the map on one sheet, with scale and sources.
Not for navigation. Depths are from government surveys and may be outdated.
Follow this lake
Every Friday by email: the Environment Canada forecast and any weather alerts in effect.