From prehistoric times to the founding of Fenton in the early 19th century, the close proximity to navigable water – the Meramec River – played an important role in the early and continuous occupation of this region. Following earlier European explorers, records show the area was occupied by settlers arriving in the 1770s. However, preceding the settlers were Native American Mound Builders which modern archeologists have associated with the great mounds at the Cahokia Mounds State Historic Park near Cahokia, Illinois. The Missouri Department of Natural Resources has designated an area in Fenton City Park with a plaque representing an even earlier civilization of the period 2,000 or 3,000 B.C.

Fenton was founded by William Lindsay Long on March 23, 1818 and named for his Welsh grandmother, Elizabeth Fenton Bennett. The original plans consisted of an eight square block area divided into 80 small lots, known today as “Olde Towne Fenton”. The town was originally incorporated in 1874.

A ferry boat was established in 1833 for ease in crossing the Meramec River, and in the same year the first post office opened its doors. In 1854 a group of businessmen formed a corporation to construct the first bridge across the river. This covered toll bridge was used until 1885 when it was replaced by an iron bridge. During the construction of the second "old iron bridge" in 1925, Gravois Road was rerouted around Olde Towne and it was at this time that Fenton gradually began to expand beyond the original eight square block area.  This bridge was replaced in 2012 with a new concrete bridge connecting Fenton with Sunset Hills.

As access to Fenton and the surrounding area improved, both the population and number and variety of businesses increased. On March 9, 1955, Fenton was reincorporated, classified as a Fourth Class City and held its first election for a new Mayor and other city officials. With renewed confidence in being able to guide a “new” city, the residents voted in favor of an annexation plan consisting of 1,500 acres of land surrounding the original eight blocks to create the City of Fenton. While the City has 4,360 residents, the population increases to between 25,000 and 30,000 individuals during the day thanks to the over 600 businesses who call Fenton their home. Fenton currently covers an area of 5.5 square miles, is located in southwest St. Louis County and is still one of the county’s best kept secrets.