Mars like object traverses night sky

A red orb that I first mistook for Mars appeared directly over head.  it seemed to be mars, but I knew mars was not in that part of the sky.  I watched it move very slowly and I actually had to find a stationary object in the foreground to verify its movement and direction.  I assumed it to be a very bright satellite or even the ISS, however it continued on an approximate magnetic heading of 160 or south by southeast.  it traversed the entire sky until it was seemingly gone over the horizon.  no detectible change in speed or heading was observed.
Witness elects to remain totally anonymous; provides no contact information.  PD