Boulder Lake has no water-specific listing in the Region 4 synopsis, so the regional defaults apply: trout/char daily quota 5 (no more than 1 rainbow or cutthroat over 50 cm), a single barbless hook is recommended, and a valid BC freshwater licence is required for anglers 16 and up. Confirm in-season changes at gov.bc.ca before you fish.

Boulder Lake sits in the Slocan River watershed group, identified in the provincial waterbody register by its Slocan-district identifier. No FISS bathymetry survey or lake-health signal is on file, so depth, clarity and shoal structure are unconfirmed; treat any on-the-water read as a first look rather than a returning angler's report.

For an angler weighing whether Boulder Lake is worth the drive, the stocking record is most of what there is to go on. The province logged 14 releases here between 1976 and 1998: roughly 29,000 Connor-strain westslope cutthroat trout (fall fry) and about 15,000 Pennask-, Premier- and Tunkwa-strain rainbow trout (fry to unrecorded life stage), for close to 44,000 fish total. The last recorded release was 1,000 Connor-strain cutthroat fall fry on 1998-09-30. Nothing has been logged since.

Twenty-eight years without a recorded top-up means Boulder Lake's fishery, if it still holds fish, runs on holdover and any natural reproduction the cutthroat and rainbow have managed rather than an active put-and-take program. Confirm locally before planning a trip.

Absent a current report, fish it on classic small-lake lines: a chironomid under an indicator over the shoals early in the season, leech patterns and a Woolly Bugger worked along any drop-off as the water warms, and a hatch-matched dry such as the Adams for an evening rise if fish are showing. Any westslope cutthroat or rainbow trout you find this long after the last stocking release should be handled as a wild fish.

No public launch, trailhead or parking information is on record for Boulder Lake. Use the coordinates above to locate it and confirm road access and any private-land crossings locally before you go; the regional default quotas above apply since the lake carries no water-specific exception in the current synopsis.