In 1788, the present site of Commerce was first occupied by French settlers, making Commerce apparently the third-oldest present site settlement in Missouri after St Louis and St. Charles. A trading post established in 1803 served as the center of commerce for the region, hence the name of the settlement.[4] In 1823, the circuit court ordered a board of commissioners to be appointed to lay out lots here. From 1864 to 1878, Commerce was the county seat of Scott County. Commerce was one of the few areas in Scott County to have uninterrupted mail service during the Civil War, as guerilla bands elsewhere made delivery unsafe for the northern carriers. Commerce, along with the German settlement of New Hamburg, were the two enclaves of Union sympathizers in Scott County during the war. On November 1, 1861, Colonel Oglesby landed in Commerce with about 3,000 men, where his soldiers soon exchanged shots with M. Jeff Thompson. On December 29, 1861, Thompson raided Commerce. On February 21, 1862, General Pope landed here with 140 troops, but when he left a week later his force consisted of 26,153 men. The island in front of Commerce was known as Cat Island at least as early as Mark Twain's time; however, it has been absorbed by Powers Island to the south. Commerce was a Methodist town, with a congregation established as early as 1825 and without a Baptist church until 1906.[5]