In Iraq, the parallel defined the limit of the southern no-fly zone from 4 September 1996 to 30 August 2003. (Before this time it had been set at the 32nd parallel north.) This airspace was controlled by Operation Southern Watch. 
In the United States it approximately forms the border between Arkansas in the north and Louisiana on the south. (The border is actually a couple of kilometres north of the parallel.) The Louisiana Territory was that part of the 1803 Louisiana Purchase which lay north of the 33rd parallel.
The parallel is part of the horse latitudes.
Starting at the Prime Meridian and heading eastwards, the parallel 33° north passes through: