Monument Lake has no water-specific listing in the current synopsis, so the East Kootenay regional default applies: trout/char daily quota 5, with no more than 1 rainbow or cutthroat over 50 cm. Confirm the current Region 4 synopsis before you fish, in case a lake-specific rule has since been added.

The lake covers 4.86 hectares and runs to a maximum depth of just 6.4 m, per the province's 1983 lake survey (A Preliminary Survey of Monument Lake). That is shallow water with nowhere to hide a deep, cool refuge, so the lake fishes as a single, evenly worked basin rather than a lake with a defined drop-off edge. It sits in the Elk River watershed on the Freshwater Fisheries Society of BC's records, carrying the waterbody identifier 00018ELKR.

Every recorded release into Monument Lake was Connor-strain westslope (Yellowstone) cutthroat trout, wild-origin fry and fall fry stocked at roughly 1,000 to 3,000 fish a planting, ten times between 1983 and 2012 for a lifetime total of 16,000 fish. The last drop was 1,000 fry on October 2, 2012. Nothing has been planted since, so what is here now is whatever that stocking built: confirm the current population with a local report or the regulations synopsis before planning a trip around it.

With no deep basin to fall back on, small-lake stillwater tactics apply across the whole surface rather than concentrated at a drop-off: work chironomids under an indicator over the shoals and open water alike, and expect cutthroat willing to come up for a dry once the surface warms.

Access, launch and facility details for Monument Lake are not confirmed. Treat it as a walk-in or backcountry stillwater until a road, trailhead or launch is confirmed locally.