The flag of Amersfoort, consists of three horizontal stripes, the upper and lower of which are white and the middle one is red. There are three squares on the brow in the colours red-white-red, with a red cross in the white field. The cross and colours come from the Amersfoort coat of arms.
The flag was adopted by the Amersfoort City Council on 28 April 1959 and can be described as follows:
| “ | Drie banen van wit en rood, waarvan de hoogten zich verhouden als 21:20:21, met op elk der banen een vierkant van het een in het ander, ter hoogte van elke baan en op het middelste vierkant een rood kruis met armen ter breedte van 1/5 van de hoogte van de middelste baan. | ” |
In English translation:
| “ | Three lanes of white and red, the heights of which compare as 21:20:21, with on each of the lanes a square of one within the other, at the height of each lane and on the middle square a red cross with arms 1/5 the width of the height of the middle lane. | ” |
The designer was city architect David Zuiderhoek. The red cross on the white field in Amersfoort's coat of arms and flag is the cross of Saint George, patron saint of the city. The use of this sign as the coat of arms of cities, regions and countries came into vogue after Richard the Lionheart put himself and his army under the protection of St George during the Second Crusade. The most famous is the flag of England. St George's Church in Amersfoort bears witness to the saint's significance for the city.