Other cities of interest include Cairo, Illinois, at the confluence of the Ohio with the Mississippi River and the southernmost and westernmost city on the river; Pittsburgh, Pennsylvania, the easternmost city on the river at the head or Forks of the Ohio, where the Allegheny and Monongahela Rivers join to create the Ohio; and Beaver, Pennsylvania, the site of colonial Fort McIntosh and the northernmost city on the river. It is 548 miles as the crow flies between Cairo and Pittsburgh, but 981 miles by water. Direct water travel over the length of the river is obstructed by the Falls of the Ohio just below Louisville, Kentucky. The Ohio River Scenic Byway follows the Ohio River through Illinois, Indiana and Ohio ending at Steubenville, Ohio, on the river.