The Lancashire flag is the flag of the County Palatine of Lancaster, that is, the historic county of Lancashire not the local authority area named after it.
The Red Rose of Lancaster is a symbol for the House of Lancaster, immortalised in the verse "In the battle for England's head/York was white, Lancaster red" (referring to the 15th century War of the Roses). The traditional Lancashire flag, a red rose on a white field, was never officially registered. When an attempt was made to register it with the Flag Institute, it was found that this flag had already been officially registered by the town of Montrose, Angus, several hundred years earlier with the Lyon Office. As the Flag Institute will not register two flags of the same design within the UK Lancashire's official flag was registered, in 2008, as a red rose on a gold field. The background was chosen as it, along with red, are the livery colours of the county.