The 225/75R16 is just over 29" tall and just under 9" wide. You'll have no trouble fitting this size tire as long as you have a 16" wheel that is 5x114.3 (same as 5x4.5) with the correct offset.
Here's a link to some aftermarket 16" wheels that will fit your jeep. Wheel Products - Discount Tire Direct
If you are looking at a used set of wheels off another jeep, post up the wheel specs or the year make and model that they came off and we should be able to tell you if they will work or not.