The pair were in critical condition and being treated for acute carbon monoxide poisoning, police said.
Emergency officials responded to the trailer after receiving a call around 1:27 pm Saturday regarding unresponsive people at a campground in Woodstock Township during the Faster Horses Festival, a multi-day country music festival.
“The caller was a friend of the five males and became concerned when he had not heard from them,” police said.
Police are investigating the “tragic incident” as suspected exposure to carbon monoxide from a generator that was located near the travel trailer.
“First responders stress the importance of keeping generators away from camping areas, tents, travel trailers, etc. as well as exhaust fumes from running vehicles,” police said.
Woodstock Township is about 80 miles west of Detroit.