Factual error: At the end of the movie, Joe Gillis is shot twice in the back and once in the chest before falling dead into a swimming pool. However, no blood from the wounds is ever seen in the pool, even after his body has been floating in it overnight.
Factual error: The cavalry sing Low Bridge (or Fifteen Years On The Erie Canal) as they trek across Texas in 1879. This was written by Thomas S. Allen in 1905 during the time the Erie canal was switched from mule power to engine power. (00:49:00)