Akron still hosts important rubber research laboratories. Mineral Resources Ohio leads the nation in the production of lime and is second in the production of clays. Ohio ranks high in the production of salt and also produces sand and gravel, stone, and coal. Agriculture Ohio's rich soils support extensive farmland. Important agricultural products include corn, soybeans, hay, wheat, cattle, hogs, and dairy items.
Transportation is facilitated by railroads and highways that crisscross Ohio and ports on Lake Erie.
Prehistoric Ohio was inhabited by the Mound Builders. Many of their great earthen mounds are preserved in state parks and in the Mound City Group National Monument. In eastern Ohio, the Iriquois Indians exterminated the Erie Indians before the arrival of Europeans. Other Native American tribes that became prominent in Ohio were the Miami, the Shawnee, and the Ottawa. European rivalry over the Ohio River led to the outbreak of the last of the French and Indian Wars in 1754.