Civil War Union Major General. He graduated from Yale University in 1831, studied law for 3 years, and opened a law office in Detroit, Michigan in 1836. In the 1840s he was a probate judge, newspaper owner, Lieutenant Colonel of a Michigan regiment in the Mexican War and postmaster of Detroit. With the outbreak of the Civil War was promoted to Brigadier General, US Volunteers on August 9, l861, and served in the Shenandoah Valley and at Cedar Mountain. After the death of General Joseph K. Mansfield at the September 17, 1862 Battel of Antietam he assumed command of the Army of the Potomac's XII Corps for a short time. As division commander with the XII Corps he fought at the battles of Fredericksburg, Chancellorsville and Gettysburg, and when the XI and XII Corps were sent to fight at Chattanooga, Tennessee in late 1863. These units remained at part of the Army of the Cumberland through General William T. Sherman's "March to the Sea" to the end of the war. In 1866 he was appointed minister resident to the Republic of Salvador. He ran unsuccessfully for Governor of Michigan in 1870, but was elected to congress in 1874. He served from March 4, 1875 until he suffered a stroke and died in the United States Capitol Building in 1878. Today an equestrian statue of General Williams, erected in 1921, stands in Belle Isle Park near Detroit. A biography of him was published as "From The Cannon's Mouth" by M. M. Quaife in 1959.