On March 29, 1942, under the authority of the executive order, DeWitt issued Public Proclamation No. 4, which began the forced evacuation and detention of Japanese-American West Coast residents on a 48-hour notice. Only a few days prior to the proclamation, on March 21, Congress had passed Public Law 503, which made violation of Executive Order 9066 a misdemeanor punishable by up to one year in prison and a $5,000 fine.

Because of the perception of "public danger," all Japanese Americans within varied distances from the Pacific coast were targeted. Unless they were able to dispose of or make arrangements for care of their property within a few days, their homes, farms, businesses, and most of their private belongings were lost forever.

From the end of March to August, approximately 112,000 persons were sent to "assembly centers" – often racetracks or fairgrounds – where they waited and were tagged to indicate the location of a long-term "relocation center" that would be their home for the rest of the war. Nearly 70,000 of the evacuees were American citizens. (1) There were no charges of disloyalty against any of these citizens, nor was there any vehicle by which they could appeal their loss of property and personal liberty.

"Relocation centers" were situated many miles inland, often in remote and desolate locales. Sites included Tule Lake and Manzanar in California; Gila River and Poston in Arizona; Jerome and Rohwer in Arkansas, Minidoka in Idaho; Topaz in Utah; Heart Mountain in Wyoming; and Granada in Colorado. (Incarceration rates were significantly lower in the territory of Hawaii, where Japanese Americans made up over one-third of the population and their labor was needed to sustain the economy. However, martial law had been declared in Hawaii immediately following the Pearl Harbor attack, and the Army issued hundreds of military orders, some applicable only to persons of Japanese ancestry.)

In the "relocation centers" (also called "internment camps" ), four or five families, with their sparse collections of clothing and possessions, shared tar-papered army-style barracks. Most lived in these conditions for nearly three years or more until the end of the war. Gradually some insulation was added to the barracks and lightweight partitions were added to make them a little more comfortable and somewhat private. Life took on some familiar routines of socializing and school. However, eating in common facilities, using shared restrooms, and having limited opportunities for work interrupted other social and cultural patterns. Persons who resisted were sent to a special camp at Tule Lake, CA, where dissidents were housed.