Denmark’s national flag is the world’s oldest continuously used sovereign-state flag.
Known as the Dannebrog, Denmark’s flag is a red field bearing a white Scandinavian cross. The cross extends to the edges, with its vertical arm shifted toward the hoist, a layout shared by several Nordic flags.
A medieval legend says the flag fell from the sky during the Battle of Valdemar in Estonia on 15 June 1219. Historians treat the story as legendary, but surviving evidence confirms the white-on-red cross as a Danish symbol by the late Middle Ages.
The Dannebrog’s claim concerns continuous use by a sovereign state, not necessarily the oldest surviving piece of cloth. Denmark uses several official and ceremonial variants, while the ordinary civil flag is known as the splitflag in Danish.