Baldwin Lake is the original. Before there was a reservoir, the valley's water collected here in a shallow alkali lake that dries out most summers, and this was the one called Bear Lake. When the dam went in down the valley in 1884 the new reservoir took the name Big Bear, and what was left was renamed for Elias J. Baldwin, the San Francisco millionaire who bought the Gold Mountain claim on the ridge above the north shore and set off the valley's second gold rush. His forty-stamp mill started up in 1875 and the mine shut later the same year, and the town of Bairdstown below it emptied out and became Doble.
The reason to stop, though, is underfoot. The low knolls around the lakebed are pebble plains: heavy clay studded with quartzite pebbles left behind by an Ice Age lake and worked to the surface over thousands of cycles as the clay swells wet and shrinks dry. What that produces is a hard, open, wind-scoured pavement that ordinary forest plants cannot take hold in, and it exists in the Big Bear Valley and in Holcomb Valley next door and nowhere else in the world.
What does grow there is correspondingly small. They are called belly plants, because that is the posture the viewing requires. Several occur only in these mountains — among them Linanthus killipii, a few white funnels marked with purple that flower in May and June and are listed as endangered; the pebble-plain population of it sits inside this reserve.
The reserve runs to 156 acres under the state Department of Fish and Wildlife, with a short interpretive loop through the knolls and the wet meadow run jointly with the Forest Service. April and May are the bloom, though a late snow will move it. The lakebed itself brings eared grebes in numbers, shorebirds on migration and bald eagles in winter.
This is Yuhaaviatam country and the east end of this valley sits at the middle of it. The habitat is fragile and slow; keep to the trail.
The closest stops worth working into your route
Roadside plaques and monuments within a short detour