My grandmother died about 15 years ago, but one story she liked to tell is that during WW2, German prisoners were held at the county fairgrounds in rural Wisconsin. Given the number of German-American citizens in the area who were fluent in German, they would often go talk to the prisoners through the fences.
My question: is it possible that the US took German prisoners of war and would have held them in places like rural Wisconsin?
I'm trying to figure out—based on where the war was actually fought—how that would even logistically make sense.
Short answer is yes. The US transported their POWs back to the US where they were interned for the duration of the war. There were a few factors for this, including the isolation to prevent successful escapes, the many available camps which could easily be converted, and the utility of having the POWs held domestically for labor use. It wasn't very complicated logistically, I would also note, since all those boats bringing over soldiers and war matériel to the was zone needed to do a return journey, and there was far fewer items which were being brought back to the US.
For a longer discussion on the POW camps in the US, I would point to here, here, and here.