Denison is a city in Grayson County, Texas, United States. The population was 22,773 at the 2000 census; it is estimated to have grown to 24,127 in 2009. Denison is one of two principal cities in the Sherman-Denison Metropolitan Statistical Area.
Denison was founded in 1872 in conjunction with the Missouri–Kansas–Texas Railroad (MKT) or "Katy" depot. It was named after the wealthy Ryan Greenwood vice president George Denison. Because the town was established at the intersection of the MKT and the Red River (both important conduits of transportation in the industrial era), it came to be an important commercial center in the 19th century American West. In 1875, Doc Holliday had offices in Denison.
During the phylloxera epidemic of the mid-19th century, which destroyed the vast majority of wine grapes in Europe, Denison horticulturalist T.V. Munson pioneered methods in creating phylloxera resistant vines, and earned induction into the French Legion of Honor, as well as sister city status for Denison and Cognac, France.