 Air defense units within the Continental United States (CONUS) were given to the Eastern and Western Air Defense Liaison Groups, with Western and Eastern Air Defense Forces activated on 1 September 1949.Central Air Defense Force (CADF) was activated as a third subordinate region under the re-established Air Defense Command in February 1951 to better organize ADC units in the Central and Southeast United States, its initial region being defined in the west as the area east of the 102nd degree of longitude, from the Canada–US border in the north to the Rio Grande border between the United States and Mexico in the south.The eastern boundary of the CADF was the area west of the 90th degree of longitude from the Michigan shoreline of Lake Superior south to the point of the Missouri, Kentucky and Tennessee state boundaries, and eastward to the Atlantic Ocean coastline along the Tennessee–Kentucky and Virginia–North Carolina border, with all areas south and west of those boundaries.