John Alexander (April 16, 1777 – June 28, 1848) was a U.S. Representative from Ohio. Born at Crowsville, in the Spartanburg District, South Carolina, Alexander attended the public schools.He moved to Butler County, Ohio, and thence to Miamisburg, Montgomery County, in 1803.He studied law.He was admitted to the bar and commenced practice in 1804.He moved to Xenia, Ohio, in 1805 and continued his profession there, also practicing in Columbus, Chillicothe, and before the Supreme Court of the United States at Washington, D.C.He was appointed prosecuting attorney in 1808 and held that office until 1833, except during the time he was a Member of Congress.