About 14.5 kilometres in length, with a maximum width of just under 2.5 kilometres, Columbia Lake has a surface area of approximately 25 square kilometres and a total volume of 72 cubic kilometres, or 581,282 acre-feet. With a shoreline of 43 kilometers, it drains a water shed that covers 869 square kilometres. There are several parks along its shore, with Columbia Lake Provincial Park at its northeast corner, Thunder Hill Provincial Park on its southwestern corner and Tilley Memorial Park at its southeastern corner. The Columbia Lake Ecological Reserve lies just east of the centre of the lake.
Relatively undeveloped compared to Lake Windermere, 13 kilometres downstream, Columbia Lake is more of a fishing lake that a tourist draw. The lake is fed by many creeks and rivers which rise in the western watershed of the Rocky Mountains, to the east, and the Purcells, to the west.
The Kootenay River, which flows into the Columbia River at Castlegar, BC, rises immediately south of Columbia Lake and at one time the two rivers, the Columbia and the Kootenay, were joined by the
Baillie-Grohman Canal to allow passage of steamships between the two river systems. Spectacularly unsuccessful, the canal was used but three times, the final one in 1902 when the captain of the passing vessel, the sternwheeler North Star,
deliberately blew out the canal's lower lock gates with dynamite to allow the transit of his vessel.
Coordinates are at a highway pullout just south of the Coy Rest Area, while most photos were taken at the rest area.