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

SULLIVAN, a county in the W. part of Indiana, bordering on Illinois, contains 430 square miles. It is drained by Busseron creek, and bounded on the W. by the Wabash river. The surface is mostly level, and the soil productive. Wheat, maize, oats, and grass are the staples. Cattle, horses, and swine are also exported. In 1850 this county produced 742,136 bushels of corn; 56,725 of wheat; 75,879 of oats, and 3751 tons of hay. There were 21 churches, and 2047 pupils attending public schools. The county contains extensive beds of bituminous coal. The Wabash is navigable for steamboats in high water. Organized in 1817, and named in honor of Daniel Sullivan, who was killed by Indians while employed in the public service. Capital, Sullivan. Population, 10,141.