The land Oregon, Illinois was founded on was previously held by the Potawatomi and Winnebago Indian tribes. In fact, later, settlers discovered that the area contained a large number of Indian mounds, most 10 to 12 feet in diameter. The name Oregon means "River of the West".
The first European to visit the land was pioneer John Phelps. Phelps first visited the area in 1829 and returned in 1833 hoping to find a suitable site to settle. Phelps found a forest and river-fed valley which impressed him enough that he built his cabin there. Other pioneers followed Phelps to this site, and Phelps helped create the first church, school, grocery store, blacksmith shop, and post office in Oregon. By December 4, 1838, due in large part to the efforts of Phelps and his brothers B.T. Phelps and G.W. Phelps, the land was claimed, subdivided and certified by the Ogle County clerk as Oregon City.