At the age of 28, John Petty homesteaded a 160-acre parcel that is now Tremonton from Main Street south. That was in 1888. The Bear River Canal was being built and land agents were scouring the country for new immigrants to populate the area. A number of families came from Nebraska and more came from a German colony in Illinois. The Tremonton townsite was laid out in 1903 and businessmen flocked to the new area. At first, not many homes were built because the families usually lived in the rear of their business structures. For that matter, the settlement didn't even have a name for several weeks. Then one of the German settlers suggested the name of his home town in Illinois: Tremont. That worked for a few years but then the postal authorities said the name was too often being confused with "Fremont" (another town in Utah). So the folks added "on" to Tremont and the name has been Tremonton ever since.

The founding of Tremonton was different from a lot of the rest of Utah in that most of the settlers were non-Mormons. However, they were virtually all progressive, industrious and willing to work with their neighbors, essential qualities for the time and the place. Growth has been pretty steady in Tremonton, leading to the city becoming the central shopping place for most of the Bear River Valley.

In April 2008, La-Z-Boy announced they were closing their factory in Tremonton and moving some of their production to a factory in Ramos Arizpe, Mexico. All 630 employees in Tremonton were laid off.