The city of Helena, Montana, is founded after miners discover gold

On October 30, 1864, Helena, Montana was founded by four gold miners. From the article:

"The city of Helena, Montana, is founded after miners discover gold
On October 30, 1864, the town of Helena, Montana, is founded by four gold miners who struck it rich at the appropriately named “Last Chance Gulch.”

The first major Anglo settlement of Montana had begun just two years before in the summer of 1862, when prospectors found a sizeable deposit of placer gold at Grasshopper Creek to the west. When other even richer deposits were soon discovered nearby, a major rush began as tens of thousands of miners scoured the territory in search of gold. In 1864, four prospectors spotted signs of gold in the Helena area while on their way to the Kootenai country, but they were eager to reach the reportedly rich gold regions farther to the north and did not to stop. But after striking out on the Kootenai, they decided to take “one last chance” on finding gold and returned. When the signs turned out to mark a rich deposit of placer gold, they staked their claims and named the new mining district Last Chance Gulch.

Eventually, Last Chance Gulch would prove to be the second biggest placer gold deposit in Montana, producing some $19 million worth of gold in just four years. Overnight, thousands of miners began to flood into the region, and the four original discoverers added to their fortunes by establishing the town of Helena to provide them with food, lodging, and supplies. But unlike many of the early Montana mining towns, Helena did not disappear once the gold gave out, which it inevitably did. Located on several major transportation routes, well supplied with agricultural products from an adjacent valley, and near to several other important mining towns, Helena was able to survive and grow by serving the wider Montana mining industry. In 1875, the city became the capital of Montana Territory, and in 1894, the capital of the new state of Montana."