United States Army, since 1956
June 14 is Flag Day in the States. It’s also the birthday of the United States Army, or rather the Continental Army which preceded it. The Army’s flag was first unveiled on it’s 181st birthday, having been officially adopted two days earlier. Today it turns 239.
It’s a complicated flag, but the way it only uses two flat colours makes it look really clean and attractive. Probably the best of any of the armed forces.