The first large-scale confinement of a specific ethnic group in detention centers began in the summer of 1838, when President Martin Van Buren ordered the U.S. Army to enforce the Treaty of New Echota (an Indian removal treaty) by rounding up the Cherokee into prison camps before relocating them. Called "emigration depots," the three main ones were located at Ross's Landing (Chattanooga, Tennessee), Fort Payne, Alabama, and Fort Cass (Charleston, Tennessee). Fort Cass was the largest, with over 4,800 Cherokee prisoners held over the summer of 1838. Many died in these camps due to disease, which spread rapidly because of the close quarters and bad sanitary conditions: see the Trail of Tears.
Throughout the remainder of the Indian Wars, various populations of Native Americans were rounded up, trekked across country and put into detention, some for as long as 2 years.
On December 7, 1901, during the Philippine-American War, General J. Franklin Bell began a concentration camp policy in Batangas--everything outside the "dead lines" was systematically destroyed: humans, crops, domestic animals, houses, and boats. A similar policy had been quietly initiated on the island of Marinduque some months before.
Japanese-, German- and Italian-Americans
In reaction to the bombing of Pearl Harbor by Japan in 1941, President Franklin Roosevelt under United States Executive Order 9066 on February 19, 1942 allowed military commanders to designate areas "from which any or all persons may be excluded." Under this order all Japanese and Americans of Japanese ancestry were removed from Western coastal regions to guarded camps in Arkansas, Oregon, Washington, Wyoming, Colorado and Arizona; German and Italian citizens, permanent residents, and American citizens of those respective ancestries (and American citizen family members) were removed from (among other places) the West and East Coast and relocated or interned, and roughly one-third of the US was declared an exclusionary zone.
Not As Brave As We Used To Be
Number of Axis POWs detained in camps on the U.S. mainland at the end of WWII: roughly 425,000.
If I read the Wikipedia entry correctly, it says the Cherokee concentration camps were the first ones in the world, not merely the US. I don't know if this is true, but it could be. If so, it's another "great" achievement in America's genocidal history.
Incidentally, the headline "Not As Brave As We Used To Be" could say "Not As Bipartisan As We Used To Be." As with the phony tea parties, the phony outrage over Obama's handshakes and bows, etc., the criticism over closing Guantanamo Bay has nothing to do with actual US security. It's all about scoring political points for Republican true believers--the ones who are drinking the Kool-Aid now to prove their loyalty to their Reagan-Bush idols.
For more on the subject, see America's Concentration Camps.