Cruse named the new mining camp Marysville for its first female resident, Mary Ralston. The mine itself was named for the parish in Ireland, where Cruse was born. In 1880, Cruse built a five-stamp mill near the Drumlummon Mine. The following year, the Marysville Post Office was opened in February, 1881 and by that time the small settlement was flourishing with numerous businesses.

In 1884, Cruse sold the Drumlummon Mine to an English Corporation for one million dollars in cash and another ½ million in stock. He then moved to Helena where he built a mansion, started a couple of banks and at the age of 50, married a young woman. However, just a year later, his new bride died in childbirth and Cruse became restless. He soon returned to the Marysville area and bought the Bald Mountain Mine on Bald Butte above town, which over the years, produced hundreds of thousands dollars in gold, silver, copper and lead ore.

Within two years of the sale of the Drumlummon Mine, the English company built 110 stamp mills to process the ore. During the 1880s and 1890s, Marysville boomed, with not only the Drumlummon Mine but also 12 additional mines in the area. The town soon boasted some 60 businesses, including 27 saloons, 7 hotels, three newspapers, grocery and drug stores, a bank, a dry-goods store, a bakery, three churches, two doctors, and numerous other businesses. At that time, the mining camp was serviced by two railroads, mining operations operated 24 hours a day, and the area sported as  many as 4,000 people. A school was later built that accommodated over 250 children.

Marysville was also a very social community during its heydays, with numerous local activities including ice cream socials, garden parties, concerts by the Marysville Brass Band, and drilling contests, whereby the miners would compete to see who could work the drill into huge boulders of hard rock, the fastest. Miners around the world competed in these contests, vying for World's Drilling Record. One such event in the Marysville area was said to have drawn over a a thousand spectators.

Unfortunately, at the turn of the century the rich ores were becoming depleted, the mine was involved in a lawsuit with the nearby St. Louis Mining Company over boundary rights, production slowed and people began to move from Marysville.