The Merionethshire flag is the flag of the historic county of Merioneth. It was registered with the Flag Institute as the official flag of the county on 2 January 2015.
The design is adapted from the seal used by the former county council. This in turn derived from the description of a banner borne by the men of Merioneth at the Battle of Agincourt, in the 17th century poem of the same name by Michael Drayton. Here he wrote of “three goats dancing "gainst a rising sun"; the shield was blue, the sun golden and the goats white. Speculation regarding this unusual arrangement suggests a connection with Cader Idris, where goats browsed and behind which the sun rose. The flag therefore both maintains a theme associated with Merioneth for six centuries and is also a highly distinctive design – no other flag features a sun in this position and the arrangement is uniquely Merioneth.