William Kennon Jr. (June 12, 1802 – October 19, 1867) was a lawyer, judge, and a U.S. Representative from Ohio.^[1] He served for one term from 1847 to 1849.

Born in Carrickfergus, County Antrim on the island of Ireland (the entirety of which was then part of the U.K.), Kennon, known locally as 'Kenno', immigrated to the United States in 1816 with his parents, who settled near Barnesville, Ohio. He was a first cousin of fellow U.S. Representative William Kennon Sr.^[1]

He attended the common schools and graduated from Franklin College, New Athens, Ohio, in 1826. Kennon studied law and was admitted to the bar in 1830.^[1]

He commenced practice in St. Clairsville, Ohio, and served as the prosecuting attorney of Belmont County from 1837 to 1841.^[1]

Kennon was elected as a Democrat to the Thirtieth Congress from March 4, 1847, until March 3, 1849. He was not a candidate for renomination, and instead resumed the practice of law. He served as judge of the court of common pleas of the fifteenth judicial district from 1865 to July 1, 1867, when he resigned.^[1]

Kennon was married to Elizabeth Kirkwood (1818–1899), daughter of Joseph Kirkwood and granddaughter of Revolutionary War hero Robert Kirkwood.^[2][3] Together, they were the parents of:

• Margaret A. Kennon (1852–1922), who married Allen C. Miller (1848–1892) in 1870.
• Newell Kirkwood Kennon (1855–1937), an attorney.^[2][4]
• Albert Wilson Kennon (1861–1949), an 1886 graduate of the Cincinnati Law School^[5] who married Ida Belle Updegraff (1868–1941), of Wheeling, West Virginia, in 1904.^[6]

He died in St. Clairsville on October 19, 1867, and was interred in Union Cemetery.^[1]