The earliest known inhabitants of Glencoe were Native Americans, who established a trail where present-day Old State Road is located. In 1803, the first Euro-American settler, Ninian Hamilton, received a Spanish Land Grant. The Missouri-Pacific Railroad extended a line to Glencoe in 1851 to serve local industries, including lime-kiln works, lumbering, and grist flour mills. Families from St. Louis built large stone homes and summer retreat cottages there, and early residents included Robert K. Woods, William L. Ewing, Alfred Carr, B.W. Lewis, A.W. Alexander, James E. Yeatman, John Whitsett, and Judge Henry McCullough. In 1854, the land speculators Woods, Christy, and Co. surveyed the town of Glencoe, creating residential lots and the grid street network that still remains today.