Emigrant travelers on their way west likely discovered small amounts of gold in the 1840's, but it took until 1868 for the first mining claims to be staked. Word of the new gold rush spread and the summer of 1868 brought an influx of people from every corner of the globe to partake in the bonanza. A torrent of mining activity followed for the next several years. In 1869 South Pass City, with perhaps 3,000 people, was Wyoming Territory's second largest town.
Every boom ends, and by the early 1870's, the local mining district collectively known as the Sweetwater mines, had passed their zenith. A small handful of hardy hangers-on remained in South Pass City through the years. Later booms, fueled by outside investment capital, kept the embers of civilized living and a connection with the larger world aglow. Today, South Pass City is among Wyoming's smallest continuously inhabited towns and is also home to its largest State Historic Site.