Where is the oil drain plug located on a 2005 Chevy Cavalier?

The oil drain plug on a 2005 Chevy Cavalier is located on the bottom of the oil pan, which is the lowest part of the engine's oil sump. To be more precise, it's on the front-most portion of the oil pan. You'll need to get under the car to see it. It's usually a bolt, and may have a 13mm or 15mm socket size (check your owner's manual to be certain).