Steubenville is one of Ohio's oldest cities. Settlement in Steubenville began with the construction of Fort Steuben in 1787. By 1840 Steubenville had 4,247 residents. Steubenville was an industrial city from the early 1800s until recently. It was a center for ceramics manufacture initially. In the second half of the 1800s iron and steel manufacture became increasingly important to Steubenville and dominated the local economy in the 1900s. The integrated steel mill that became the center of Steubenville's economy was built by La Belle Iron in 1899 and expanded over the years. Through mergers, it eventually became the property of the Wheeling Pittsburgh company. This mill is just South of town and spans the Ohio River. By the late 1900s the Wheeling-Pittsburgh mill was essentially all that was left of Steubenville's industrial economy. The Wheeling-Pittsburg mill closed in 2005 and is being demolished as of 2014. Because of Steubenville's long history as a regional commercial center, downtown Steubenville is substantial. Steubenville is still a commercial center for a large but declining area that includes Mingo Junction Ohio and Weirton West Virginia. Steubenville's peak population was 37,651 in 1940. It's current population is 18,429 (2012).