During World War II, approximately 120,000 Americans of Japanese ancestry, including nearly 70,000 US-born Japanese Americans, were forcibly removed from West Coast areas and interned in camps. The US entered World War II after the bombing of Pearl Harbor on December 7, 1941. Fueled by war hysteria and anti-Japanese sentiment, calls for the mass evacuation or removal of Japanese "enemy aliens" arose in the wake of this surprise attack. In February 1942, Pres. Franklin Delano Roosevelt signed Executive Order 9066, which authorized the Secretary of War to prescribe military areas, "from which any or all persons may be excluded." This executive order paved the way for the eventual internment of civilians of Japanese ancestry, including large numbers of US-citizen Japanese Americans. Japanese American families, many of them farmers, were forcibly removed from their homes on the West Coast and transported to "relocation centers" or internment camps in remote, interior sites, many of them in the desert. They were held in these camps, surrounded by barbed wire, until nearly the last days of the war. The last of the camps closed in 1946.
Scholars have identified four major factors behind interment: a history of racial prejudice and anti-Asian sentiment; wartime hysteria; a failure of intelligence and leadership; and economic motives. The interment of Japanese American civilians during World War II is now recognized as one of the worst violations of civil rights and civil liberties in US history. In 1988, after a long fight for redress, the US government issued an official apology to the internees and awarded each of the survivors $20,000 in compensation.
There are many primary sources relating to this history available online. Try these links to start your research:
Smithsonian – A More Perfect Union (Collection Search) and (Removal Process)
University of California, Japanese American Relocation Digital Archive and the themed collection on the 442nd Regimental Combat Team
National Archives, including Lessons and Relocation Records