Helena: By 1888, about 50 millionaires lived in Helena, more per capita than in any city in the world. They had made their fortunes from gold. About $3.6 billion (in today's dollars) of gold was taken from Last Chance Gulch over a 20-year period. The Last Chance Placer is one of the most famous placer deposits in the western United States. Most of the production occurred before 1868. This large concentration of wealth was the basis of developing fine residences and ambitiou architecture in the city; its Victorian neighborhoods reflect the gold years. The numerous miners also attracted the development of a thriving red light district. Among the well-known local madams was Josephine "Chicago Joe" Airey, who built a thriving business empire between 1874 and 1893, becoming one of the largest and most influential landowners in Helena.

n 1885, when the Montana Club was founded (a place Twain visited), Helena was enjoying a sky rocketing boom. Fueled by its position as capital of the state, its proximity to gold fields and silver, lead deposits, and the arrival two years before of the North Pacific Railway which soon quadrupled the population and substantially increased the traffic in goods into and out of the town. In 1888 the town was crawling with millionaires, 50 in all, about 1 for every 250 people. But by the time the Clemenses arrived the town was less opulent. The panic of 1893 had destroyed the boom. Helena never regained its once fabulous prosperity.

East Helena: In 1888, a large lead smelter was built on the banks of Prickly Pear Creek in the Helena Valley by the Helena and Livingston Lead Smelting Company. In 1898, the American Smelting and Refining Company (ASARCO) purchased the 160 acre site. ASARCO operated the smelter until 2001. East Helena grew up around that enterprise. For over a century, the smelter processed 70,000 tons of lead bullion a year, and provided a livelihood for thousands of families. It also produced untold tons of toxic contaminants.