In 1870, with money saved from his business in Fort Garland, he moved to what is now
Walsenburg. He soon became a leader in the town, and it was incorporated as a city in 1873 and named for him. The original spelling was "Walsenburgh", but the final "h" was eventually dropped. He was elected the city's first mayor and served on the city's board of trustees. Over time in southern Colorado, Walsen accumulated large holdings of land and large herds of livestock, including sheep and cattle. In 1889, he started Walsenburg's first bank, eventually selling it in 1904. In addition, he was in the
railroad tie business, selling ties and
utility poles to railroads laying new track in southern Colorado and New Mexico. ==Colorado State Treasurer==