There are 2 Class III receiver hitches available for your 2011 Town Car, the Draw-Tite Class III, part # 41116 and the Curt Class III, part # 13707. Both Hitches will work great for you.
Luckily enough, on your particular vehicle, the vast majority of the cross bar will be hidden behind the rear bumper structure, with a very small amount of the bottom of the cross bar and the receiver opening visible below the bumper.
Town Car models with the dual exhaust will require the removal and... view full answer...