The modern Wisconsin ANG received federal recognition on 25 June 1947 as the 126th Fighter Squadron at General Mitchell Field, Milwaukee. It was equipped with F-51D Mustangs and its mission was the air defense of the state. On 6 October 1948 the 176th Fighter Squadron was formed at Truax Field, Madison, also equipped with F-51D Mustangs with an air defense mission. 18 September 1947, however, is considered the Wisconsin Air National Guard's official birth concurrent with the establishment of the United States Air Force as a separate branch of the United States military under the National Security Act.