The internment of Japanese Americans in the United States during World War II was the forced relocation and incarceration in camps in the interior of the country of between 110,000 and 120,000 people of Japanese ancestry who had lived on the Pacific coast. Sixty-two percent of the internees were United States citizens. President Franklin D. Roosevelt ordered the incarceration shortly after Imperial Japan's attack on Pearl Harbor.
Incarceration was applied unequally due to differing population concentrations and, more importantly, state and regional politics: more than 110,000 Japanese Americans, nearly all who lived on the West Coast, were forced into interior camps, but in Hawaii, where the 150,000-plus Japanese Americans comprised over one-third of the population, 1,200 to 1,800 were interned. The internment is considered to have resulted more from racism than from security risk posed by Japanese Americans.
President Franklin D. Roosevelt authorized the deportation and incarceration with Executive Order 9066, issued February 19, 1942, which allowed regional military commanders to designate "military areas" from which "any or all persons may be excluded. This power was used to declare that all people of Japanese ancestry were excluded from the entire West Coast, including all of California and much of Oregon, Washington and Arizona, except for those in government camps. Approximately 5,000 Japanese Americans voluntarily relocated outside the exclusion zone before March 1942, and some 5,500 community leaders arrested after the Pearl Harbor attack were already in custody. But, the majority of nearly 130,000 mainland Japanese Americans were forcibly relocated from their West Coast homes during the spring of 1942.
Hope this helps :)
