| State: | Ohio |
| District: | 2nd |
| Term Start: | March 4, 1857 |
| Term End: | March 3, 1859 |
| Preceded: | John Scott Harrison |
| Succeeded: | John A. Gurley |
| State Senate2: | Ohio |
| District2: | 1st |
| Term Start2: | January 6, 1862 |
| Term End2: | January 3, 1864 |
| Preceded2: | Thomas W. Key George W. Holmes E. A. Ferguson |
| Succeeded2: | Thomas H. Weasner Benjamin Eggleston Thomas H. Whetstone |
| Alongside2: | Benjamin Eggleston Thomas H. Whetstone |
| Party: | Democratic |
| Birth Name: | William Slocum Groesbeck |
| Birth Date: | 24 July 1815 |
| Birth Place: | Kinderhook, New York |
| Death Place: | Cincinnati, Ohio |
| Restingplace: | Spring Grove Cemetery |
| Spouse: | Elizabeth Burnet |
| Alma Mater: | Augusta College (Kentucky) Miami University |
| Relations: | Madeleine Ives Goddard (granddaughter) |
| Signature: | William S. Groesbeck (signature).png |
William Slocum Groesbeck (July 24, 1815 – July 7, 1897) was an American lawyer and politician who served one term as a U.S. Representative from Ohio from 1857 to 1859.
Groesbeck was born in Kinderhook, New York, on July 24, 1815.[1] He was the son of John H. Groesbeck (1790–1862) and Mary (née Slocum) Groesbeck (1794–1854). The Groesbeck family was originally from Amsterdam.[2] William's sister, Margaret Groesbeck, was married to his wife's brother, Robert Wallace Burnet. Through the marriage of his sister, Olivia Augusta Groesbeck, he was the brother-in-law of prominent Civil War general Joseph Hooker.
Groesbeck moved with his parents to Cincinnati, Ohio, in 1816. He attended the common schools and Augusta College in Kentucky. He was graduated from Miami University, Oxford, Ohio, in 1835 and was responsible for founding the Miami University chapter of Alpha Delta Phi, the first fraternity chapter west of the Allegheny Mountains.
He studied law and was a law clerk in the office of Salmon P. Chase (later the Governor of Ohio and Secretary of the Treasury during the Lincoln administration). He was admitted to the bar in 1836 and commenced practice in Cincinnati, Ohio.
In 1851, he served as member of the State constitutional convention and, in 1852, he served as commissioner to codify the laws of Ohio. Groesbeck was elected to succeed John Scott Harrison as a Democrat to the Thirty-fifth Congress, serving one term from March 4, 1857, to March 3, 1859. He was an unsuccessful candidate against John A. Gurley for reelection in 1858 to the Thirty-sixth Congress.
He served as member of the Peace Convention of 1861 held in Washington, D.C., in an effort to devise means to prevent the impending war. From 1862 to 1864, he served in the Ohio State Senate and in 1866, he served as delegate to the Union National Convention at Philadelphia.
He was one of U.S. President Andrew Johnson's counsel in his impeachment trial in 1868.
In 1872, he was nominated for president of the United States by Liberal Republicans who were displeased with Horace Greeley, but his ticket was forgotten during the excitement of the campaign, at the end of which he received one electoral vote for vice-president.He served as delegate to the International Monetary Conference in Paris, France, in 1878.
Groesbeck married Elizabeth Burnet (1818–1889), daughter of Judge Jacob Burnet.[2] Together, they were the parents of:[3]
His wife died on April 6, 1889, leaving five living children.[2] Groesbeck died in Cincinnati, Ohio, on July 7, 1897, and was interred in Spring Grove Cemetery.