Alder Gulch, between Virginia City and Alder, was one of the most significant placer mining districts in the U.S., producing over 2.5 million troy ounces of gold between 1863 and 1889, with miners recovering over $40 billion in gold at today’s prices. After prospectors discovered placer gold there in 1863, the search began for the mother lode, and gold-bearing quartz veins south of Virginia City were heavily mined in the late 1800s, yielding about 170,800 troy ounces of gold. Over time, gold eroded from these veins and was transported, concentrated, and preserved in the gravels and channels of Alder Gulch. The quartz veins originated from fluids generated deep in the earth’s crust over a billion years ago that moved through planes of weakness in older metamorphic rock, which is widely exposed in parts of the Tobacco Root Mountains, Ruby Range, and Gravelly Range bordering the gulch. From 1915 to 1923, articles in The Madisonian discussed geologists’ views that a gravel-filled channel beneath volcanic rock on the east side of Alder Gulch might contain large amounts of placer gold, but limited drilling never found such a buried channel. The gulch’s devastated landscape resulted from gold dredging between 1899 and 1922, when dredge boats floating on self-made ponds used buckets, conveyors, sluices, and shakers to recover gold from deep gravel and leave behind the piles still visible today.