The internment of Japanese Americans during World War II primarily affected those Japanese Americans who lived on the West Coast of the United States. This region, including states such as California, Oregon, and Washington, had a significant Japanese American population at the time. Following the attack on Pearl Harbor in 1941, the U.S. government issued Executive Order 9066, which authorized the forced relocation and internment of over 120,000 Japanese Americans, the majority of whom were living on the West Coast. They were placed in internment camps for the duration of the war, despite the fact that the majority were American citizens. This internment was a deeply controversial and later recognized as a violation of civil liberties.