The Tule Lake camp, in the Klamath Basin of northern California near the Oregon border, was the largest of the ten camps where the U.S. government incarcerated people of Japanese ancestry during World War II, holding more than 18,000 people at its peak. It opened in May 1942, and in 1943 it became a segregation center for incarcerees labeled "disloyal", often because of how they answered a flawed loyalty questionnaire. It had the heaviest security of any camp and was the last to close, in March 1946. Today the site is part of Tule Lake National Monument, managed by the National Park Service, which preserves the camp jail and other remains.
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