A Presbyterian chapel school was erected in 1883 with William R. Campbell as pastor. However, most Mendonites were Mormons, and in the period from 1887 to 1890, because of their plural wives, a number of the men were sent to jail under the Edmunds-Tucker Act.

After 1872 Mendon went from a self-sufficient pioneer hamlet to an irrigated wheat farming area dependent upon external markets. Farming was central to the town's existence. After 1890 diversification of farming included the raising of alfalfa, sugar beets, dairy cows, and draft horses. In the twentieth century, mechanization and market farming altered the community's character, and Mendon became a mother community to new towns as many of its young people moved away to farms in southern Idaho.

Joseph Baker built a rock dance hall in Mendon in 1896, apparently the first in the valley. A new schoolhouse was constructed in 1899. In 1906-07, a railroad spur line linked Mendon and Hyrum. By 1907 Mendon was known for its thoroughbred horses, particularly of the draft breeds. The Forster Hotel was a favorite haven for weekend visitors to the Mendon horse races.