 The delineation was again adjusted in March 1956 to the region generally to the east of the 114th degree of longitude, roughly along the eastern borders of Idaho, Nevada and California from the Canada–US border in the north to the Mexican border in the south.The southeast region east of the Mississippi River to the Gulf of Mexico was reassigned to EADF.Central Air Defense Force was inactivated on 1 July 1960, with its assigned units reassigned either to 29th, 30th or 33rd Air Divisions, or to the new Air Defense Sectors created with the advent of the Semi Automatic Ground Environment (SAGE) system.