The 1854 Gazetteer of the United States by Thomas Baldwin shows:

MACOUPIN, a county in the W. S. W. part of Illinois, has an area of 800 square miles. It is drained by the Maconpin, Otter, and Cahokia creeks, from the first of which the name is derived. The surface is moderately diversified and the soil excellent. The prairies of the county are more extensive than the forests. Indian corn, wheat, oats, potatoes, pork, and butter are the staples. In 1850 it produced 1,598,829 bushels of corn: 77,022 of wheat; 257,101 of oats, and 297,707 pounds of butter. It contained 20 churches, and 2003 pupils attending public schools. The county is intersected by the Alton and Springfield railroad, and by the Alton and Terre Haute railroad, not yet finished. Capital, Carlinville. Population, 12,355.