Georgetown Lake

Georgetown Lake sits at 6,336 feet in the saddle between Anaconda and Philipsburg, tucked under the eastern flank of the Anaconda-Pintler Wilderness in southwest Montana. It covers 2,818 acres but holds only about 43,000 acre-feet of water, and that ratio tells you almost everything you need to know: this is a broad, shallow, sun-warmed basin averaging just 15 feet deep. Where most Montana reservoirs are canyon plugs with steep walls and cold, sterile depths, Georgetown is a fertile bowl of weed flats and shoals. It is, by a wide margin, the state's best-known and most beloved stillwater for fly anglers.

Shallow plus fertile equals fast growth. The lake's extensive submerged vegetation supports enormous populations of scuds, chironomids, damselfly and dragonfly nymphs, and leeches, and trout convert that biomass into weight at a rate river fish in the surrounding drainages cannot match. Rainbow trout are the headline fish, supported by heavy annual Eagle Lake-strain plants. Brook trout are equally important here and unusual in that they are both stocked in large numbers and reproduce naturally, giving Georgetown a brookie population dense enough that Montana FWP has historically encouraged harvest. Kokanee salmon add a landlocked-sockeye dimension that drives much of the winter fishery, and westslope cutthroat round out the species list.

The fly angler's year opens at ice-out, usually sometime in April or early May depending on the winter. Chironomids come off almost immediately over the weed flats, and a pupa suspended under an indicator in eight to fifteen feet of water is the single most productive presentation on the lake in spring. By early June the damselfly migration begins, with nymphs swimming toward shoreline vegetation and emergent stems in numbers that turn otherwise cautious trout reckless. This is the window when an olive damsel nymph retrieved with short, twitchy strips near the weed edges outfishes everything else.

Then come the gulpers. From roughly late June through August, Georgetown produces the dense Callibaetis emergences that made its reputation. On calm mornings, pods of rainbows and cutthroat cruise the flats in loose circuits, porpoising through drifting duns and spinners, and a fly angler in a float tube or from a quietly anchored boat gets legitimate sight-fishing at rising trout in stillwater. Reading the direction of a cruising pod and leading it by several feet is the whole game. When the wind comes up, as it does most afternoons at this elevation, the flat-water fishing shuts off and the lake reverts to a strip-and-search fishery with leeches, buggers, and scud patterns along the drop-offs.

Fall cools the water back down and brings some of the best streamer and scud fishing of the year before ice forms, and then Georgetown converts into one of Montana's busiest winter ice fisheries, with brook trout and kokanee drawing crowds of shelters onto the frozen flats. Very few Western lakes fish well in all four seasons; Georgetown is one of them, and its combination of easy access, forgiving depth, and world-class insect life makes it approachable for a newcomer to stillwater and endlessly technical for anyone who wants it to be.

Georgetown is a shallow, highly productive reservoir. The FWP bathymetric survey lists an average depth of only 15 feet across 2,818 acres, with 43,453 acre-feet of storage; the chart does not print a maximum depth figure, and in practice the deepest holes near the dam and along the old channel are the exception rather than the rule. Because so much of the lake bottom sits inside the photic zone, submerged vegetation blankets huge areas of the basin, and the depth chart's broad, widely spaced contours reveal exactly what you would expect: expansive flats and shoals separated by subtle troughs rather than dramatic structure.

That shallowness has consequences. The lake warms readily through summer and does not stratify the way a deep coldwater lake does, so trout are never far out of fly-rod reach; there is no thermocline retreat that pulls the fish beyond a floating or intermediate line. Water clarity is generally good in spring and fall and can turn greener as summer algal productivity peaks. The weedbeds themselves are the primary structure on the lake, and learning to fish weed edges, channels between beds, and the transition from vegetation to open bottom is more valuable than any depth reading.

Forage is the other defining feature. Scuds are abundant year-round in the vegetation, chironomids emerge from ice-out through fall, damselfly and dragonfly nymphs live in the weeds, and Callibaetis mayflies hatch prolifically from early summer into August. Leeches round out the menu. Fish grow quickly on this buffet, and their condition shows it.

Georgetown supports a large and genuinely popular winter ice fishery. Brook trout and kokanee are the primary winter targets, and the shallow, uniform basin means productive water is available almost anywhere the ice is safe. Shelter towns build up on the flats through mid-winter and the lake draws anglers from across southwest Montana. Fly anglers who jig can fish small chironomid and scud imitations effectively under the ice. Verify current FWP winter season dates and check ice thickness locally before heading out.