"The Rockford area was first visited and inhabited by Native American cultures, such as the Hopewell, Mascouten, and Ottawa tribes. There have not been archaeological finds of Native American settlements in the Rogue River valley, but their trails branched through the area and were noted by early surveyors.
The first important settler of what would become the city of Rockford was Smith Lapham, who came to Kent County in 1843 after living in Washtenaw County for 18 years. Smith Lapham came to the banks of the Rogue to assist in the completion of a dam and sawmill begun by a William Hunter. Hunter gave Lapham 40 acres of land on the east side of the Rogue for his trouble, and Lapham stayed there for the rest of his life. Hunter shortly left the area
Lapham built his own sawmill on his side of the river, which was completed by 1844. Other settlers soon followed, including John Long, Freeman Burch, and William Thornton. By the fall of 1845, the settlement had about five houses. Since the settlement existed largely on land owned or sold by Smith Lapham, it became known as Laphamville. In 1856, it was first platted as Laphamville by William Thornton.
By 1865, the Grand Rapids and Indiana Railroad Company had begun a railroad extending northward through the village. The railroad had been advising the residents to adopt a shorter name, and when a newly arrived resident from Rockford, Illinois proposed the name of his former town; He claimed it to be derived from the shallow, rocky ford below the dam where travelers crossed the river. The new name was narrowly approved. It was replatted under the name Rockford in 1865 and incorporated as the Village of Rockford in June 1866 with 315 inhabitants."Information provided by The City of Rockford
https://www.rockford.mi.us/community/about_rockford/history.php