Sawmills and flour mills were built, irrigation systems were dug, and a municipal government was created to oversee public laws and improvements. The city was incorporated in 1868, a year after the first co-operative store was founded, starting what became a burgeoning commercial district. Upon the arrival of the Rio Grande Western Railroad in 1890, both the local population and the city's prosperity increased dramatically. By 1900 Mt. Pleasant had grown to nearly 3,000 persons, the largest size reached by any city in Sanpete County to that time, and the city had earned one of its nicknames, "Hub City."

The town's newfound wealth became immediately apparent in a building boom which saw the replacement of small, wood-frame commercial buildings with much more impressive, architect-designed stone and brick structures such as the 1888 Sanpete County Co-op, the Gentile store which competed with the ZCMI, or Mormon, store. The resulting Main Street district is today so architecturally distinctive that the two-block-long area has been listed on the National Register of Historic Places. Equally striking were the Victorian churches, schools, and residences which replaced the simpler adobe and log buildings of the pioneer period.