During an 1859 visit to the Cache Valley settlements, Orson Hyde, President of the Quorum of the Twelve Apostles, accompanied by Apostle Ezra Benson, on 19 December organized the Mendon Ward. Apostle Benson selected the Massachusetts town of his birth as the name of the new ward. On 19 February 1860 Andrew Shumway was ordained bishop under the hands of LDS Church President Brigham Young and Apostle Benson.

A pine log school/meeting house was erected in 1860. Gardner's Creek was dammed to irrigate the farms during a drought. A U.S. Post Office was established in the spring of 1861 with Willie as postmaster. Joel Ricks established a ferry across the Little Bear River, providing a direct route from Logan to Mendon. In 1863 Mendon settlers provided aid to the wounded soldiers who participated in the Bear River Massacre under the command of Colonel Patrick Connor. Other frontier incidents involved natives and wild bears. For instance, Henrietta Bird in 1863 used a flatiron and a poker to kill a bear that made the mistake of entering her kitchen. After one of Chief Pocatello's braves was killed in Mendon, a child was kidnapped. For protection, construction on a never-finished rock wall around Mendon was undertaken.