A convenient beginning date for the history of the Arnold area would be 1776, with the order of King Charles III of Spain to open a land route to stimulate commerce between the trading posts of St Louis and Ste Genevieve. As part of the route, the Lt Governor of Louisiana, Francois Cruzat, offered 1050 arpents of land (about 893 acres) to anyone who would build and operate a ferry across the Meramec. Jean Baptiste Gamache completed the project in 1776 and established what was known as the lower ferry at the location where State Route 231 crossed the Meramec. Gamache's ferry was part of the King's Trace or El Camino Real (the Royal Road). The road was marked out in 1789 on an old Indian trail and led from St Louis south, across Gamache's ferry, to Kimmswick, Sulphur Springs, Ste Genevieve, and eventually to New Madrid. After 1850, this route became known as Telegraph Road because the first telegraph line in Missouri followed the route with the first poles embedded along the old trail.

Gamache was one of, if not the first permanent settlers in the Arnold area. He claimed the 1050 arpents of land and settled and cultivated land in the area until 1780, when he was ordered away on account of Indian disturbances. Other land claims in the Arnold area involved a "league of land" (approximately 6000 acres) comprising 90% of the current corporate limits of Arnold and the almost coterminous boundaries of Water District No 1. Land records showed that the property was involved in a land claim settlement, referred to as Decision No 877. This decision resulted in the apparent transfer of the land or claim from Gabriel Cerre to Auguste Chouteau and Antoine Soulard, the surveyor general of Upper Louisiana. Other earlier settlers involved in land claims in areas south of Gamache's ferry included Hardy Ware and Auguste Gamache.

With continued immigration, more and more land was settled and cultivated. Most of the immigrants were from northern Europe, with Germans predominating. Records from Immaculate Conception Church, founded in 1840 and located on Church Rd just west of U S 61-67, showed parishioners from Bavaria, Alsace, Lorraine, and Rheno-Prussia. The first Lutheran Church in Jefferson County, St. John's, was established in 1848 at Beck (area at the junction of Richardson Rd & U S 61-67.

In 1858, the Iron Mountain Railroad (now the Mo-Pac) was completed and ran from Plum Street in St Louis to Pilot Knob. The route ran past Jefferson Barracks and Cliff Cave in St Louis County, and crossed the Meramec less than one mile above the mouth of the river. In 1867, the Hillsboro-Lemay Ferry road was constructed and used by stagecoaches. In later years this road, with its many hills, was used as a testing route for automobiles manufactured in St Louis.

An atlas of Jefferson County compiled in 1876 showed approximately 70 dwellings in the current Arnold corporate limits. Also shown on the map was the Village of Maxville, incorporated in 1874 and located around the junction of Lemay Ferry Rd and State Route 141. The village was named after Max Stengel who established the first business. A post office was established in 1873, and the population was listed in the 1876 atlas as 100. Other interesting features of the map include the many orchards, and a schoolhouse, located on the east side of current U S 61-67 between Glenn and Arnold Tenbrook Rd. The map also showed that a George Arnold owned property adjacent to current U S 61-67 between Church and Arnold Tenbrook Roads. Later maps showed a settlement named Arnold at the site of Arnold's property, with the current city also named after him.

A later map, dated 1898, showed that not much growth had occurred between 1876 and 1898. It also showed a school at the current location of Rockport Elementary School. Ownership of the land in the area recently flooded had passed from E J Gay to John and Annie Ten Brook. John Ten Brook, in about 1902, donated a four-acre tract of land close to the Meramec River to get a depot and side track along the Frisco Railroad. The railroad was completed in 1902.