| Office: | President pro tempore of the Mississippi State Senate |
| Term End: | January 7, 1896 |
| Term Start: | January 7, 1890 |
| Termstart2: | January 5, 1886 |
| Termend2: | January 7, 1896 |
| Termstart3: | January 1878 |
| Termend3: | January 1880 |
| State House3: | Mississippi |
| State Senate1: | Mississippi State |
| Predecessor: | J. P. Walker |
| Successor: | James T. Harrison |
| Birth Date: | 29 December 1836 |
| Birth Place: | Marshall County, Mississippi, U.S. |
| District1: | 32nd |
| Prior Term1: | 7th (1886–1896) |
| Termstart1: | January 1908 |
| Termend1: | January 1912 |
| Predecessor1: | George R. Hightower |
| Successor1: | Lee M. Russell |
| Successor2: | W. F. Love |
| District3: | Lafayette County |
| Death Place: | Glenville, Mississippi, U.S. |
| Party: | Democratic Party |
| Children: | 8 |
Robert Aaron Dean (December 29, 1836 – November 19, 1912) was an American politician and farmer. He served in both houses of the Mississippi Legislature, and was the President Pro Tempore of the Mississippi State Senate from 1890 to 1896.[1] [2] He represented Lafayette County.[3]
Robert Aaron Dean was born on December 29, 1836, near Chulahoma, Mississippi. He was the son of Russell Dean, who was of English and Scottish descent; and his wife Louisa Ann (Alsup) Dean, who was of Welsh and Irish descent. Dean attended the private schools of his native Marshall County, Mississippi, and became a farmer.
When the American Civil War began in 1861, Dean enlisted in the 19th Mississippi Infantry Regiment as an Orderly Sergeant, and by 1863 was promoted to Major, at which rank he served until the end of the war.
In 1877, Dean was elected to represent Lafayette County as a Democrat in the Mississippi House of Representatives for the 1878–1880 session, and entered office on January 8, 1878. Dean then represented the 7th District (Lafayette County) in the Mississippi State Senate from 1886 to 1896.[4] [5] In 1890, Dean was elected by acclamation to the position of the senate's President pro tempore.[6] He was a delegate at the 1890 Mississippi Constitutional Convention and chaired the penitentiary committee that banned convict leasing. In 1892, Dean was re-elected to the presidency pro tempore, defeating Senator John M. Simonton with a vote of 30 to 12.[7] His tenure as president pro tempore continued through the 1894 session.[8] In 1896 Dean was succeeded in the Senate by W. F. Love.[9] From 1900 to 1903, Dean was part of the Commission that supervised the construction of the new Mississippi State Capitol building. On January 25, 1908, Dean was elected to replace George W. Hightower, who resigned, to represent the 32nd District (also Lafayette County) in the State Senate. He was succeeded in the state senate by Lee M. Russell.
Dean died near Glenville, Mississippi, on November 19, 1912.[10]
Dean was a Democrat, a Baptist, and a Mason. He married Lucy Ann Langston on February 2, 1864, and they had eight children together, all of whom were living as of 1908. Their names were Russell Langston, Thomas Greenwood, Joseph James, Robert Aaron Jr., Louanner, Georgia, Minnie, and Hardy Mott.