The Cessna took off from Waukegan headed to Canada for a fishing trip. The Price County Sheriff's Office says the airplane crashed at 3:21 a.m. Saturday near the city of Phillips.
Everyone on board was killed. Two of the victims were identified as Charles Tomlitz and Thomas DeMauro, according to Bensenville School District 2 where they both worked.
Tomlitz was the school district's maintenance director and DeMauro was a physical education teacher.
The men were with their sons and it was a trip that they had done before.
WSAW-TV reports that the crash victims were all adults, but no names have been released. All victims are believed to be from the Chicago area.
National Transportation Safety Board investigators say there was a discussion between the pilot of the plane and air traffic controllers about "local weather phenomenon." Soon after, the aircraft dropped off radar.
The Associated Press contributed to this report.