Congress in the Archives

On the morning of December 7, 1941, Japanese bombers staged a surprise attack on U.S. military and naval forces in Hawaii. In a devastating defeat, the United States suffered 3,435 casualties and the loss of or severe damage to 188 planes, 8 battleships, 3 light cruisers, and 4 miscellaneous vessels. Japanese losses were less than 100 personnel, 29 planes, and 5 midget submarines.

Four years after the attack, Congress established the Joint Committee on the Investigation of the Pearl Harbor Attack. Their task was to make a full and complete investigation of the facts relating to the events and circumstances leading up to or following the attack. In its investigation, the committee sought to determine whether shortcomings or failures on the U.S. side might have contributed to the disaster and, if so, to suggest changes that might protect the country from another attack in the future. The committee’s public hearings began on November 15, 1945, and continued until May 31, 1946.

The Radar Plot of Detector Station Opana was an exhibit of the Joint Committee. The 22 x 31-inch radar plot was made by Privates Joseph L. Lockard and George Elliot at the Opana Radar Station on the morning of December 7, 1941. It indicated a large number of aircraft approaching the island of Oahu. The control officer whom Lockard and Elliot called believed the radar signals announced the approach of American B-17s scheduled for arrival the same day. It wasn’t until they arrived back at camp that they learned of the Japanese attack and surmised that the planes they had observed on the radar were the same ones who led the attack.

Learn more about the documents relating to the Pearl Harbor attack by visiting our featured document on the Day of Infamy.

Radar Plot from Station Opana, exhibits compiled 11/15/1945 - 5/31/1946, Records of the Joint Committees of Congress (ARC 2600930)