A 1949 provincial survey put Rosebud Lake at roughly 14.8 hectares, with a maximum depth of 14.9 m and a mean depth of 9.1 m, a genuine two-tier basin with real shoal-to-drop-off structure. A more recent Go Fish BC profile lists a somewhat different reading, 18 m deep over 13.36 ha, so treat either figure as approximate rather than exact. The lake sits at roughly 809 m elevation and typically clears of ice mid-to-late April. Provincial stocking records show a single release of westslope cutthroat trout here in 1930; there has been no hatchery program since, and today's rainbow trout fishery runs entirely on wild spawning.

Rosebud is a wild rainbow lake, and a genuinely good one: fish to 3.5 kg (8 lb) have come on size 16 chironomid patterns, with typical fish running 30 to 40 cm. The first weeks after ice-off bring strong chironomid fishing, worked short-leader tight to shore or long-leader under an indicator (chironomid under an indicator); a Ice Cream Cone Chromie pupa is the standard pattern. That holds through late May and June, when evening mayfly hatches call for bead-head Prince and Hare's Ear emergers followed by dries: Blue Winged Olives, Royal Wulffs, Green Drakes and Adams Irresistibles. Mid-July brings travelling sedge hatches and topwater action, then summer pushes the fish deeper, best worked with a full-sink line, Woolly Buggers and dragonfly nymphs. From September into November, fish water boatman and scud patterns with an erratic retrieve, especially once the first frost triggers a boatman nuptial flight.

Reach Rosebud Lake from Salmo: east on Highway 3 for 14.3 km past town, then south on Highway 6 toward the U.S. border for 9 km, then Rosebud Lake Road for a final 6 km to the lake. A cartop launch and a small wilderness campsite sit at the water, with a single outhouse and no other facilities, so plan to pack in everything else. In summer, the Salmo River fishes well and makes an easy add-on for the same trip.