Japanese naval force position 400-500 miles from American Pacific coast according to the U.S. Joint Intelligence Committee. Daily summary dated 14 December 1941

An item referred to the CNO reporting that a Japanese naval force including an aircraft carrier was positioned 400-500 miles off the American west coast north of San Francisco.

Source

Map Room Papers (Roosevelt Administration) mr0422a. U.S. Joint Intelligence Committee. Daily summary No. 4 Dated 14 December 1941.