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

PEORIA, a county in the N.W. central part of Illinois, has an area of 650 square miles. The Illinois river and Peoria lake form the S.E. boundary. It is drained by Spoon river, and by Kickapoo, Elbow, and Copperas creeks. These streams are bordered with tracts of timber, which are separated from each other by beautiful undulating prairies. The soil is uniformly and highly productive. Indian corn, wheat, oats, hay, pork, potatoes, and wool are the staples. In 1850 there were raised 1,013,289 bushels of corn: 185,157 of wheat; 138,718 of oats; 12,553 tons of hay, and 40,225 pounds of wool. It contained 19 churches, 3 newspaper offices, and 3260 pupils attending public schools. Valuable mines of stone coal have been opened. The Illinois river is navigable by steamboats along the border. The county is intersected by the Peoria and Oquawka railroad. Organized in 1825, and named from the tribe of Indians who possessed the soil. Capital, Peoria. Population, 17,547.