where is the spare tier located on 2001 Lincoln navigator ????

Under the back, between the rear bumper and rear axle.

The tire is most liukely located at the rear of the car underneath between the two rear wheels

Navigators do not have TIERs..They have TIRES though.

The spare for most SUV is are under the vehicle, between the rear axle and rear bumper.

There is a place where you will insert your tire jack is handle to turn the crank to lower the tire. Consult your owner is manual for the exact location. It is probably at the top edge of the bumper, hidden by the hatch back (that is where it is located on my Trail Blazer, anyway).

The tire is underneath the rear cargo area of the vehicle or where the third row seat is if u have them.
There is a hole in the bumper with a rubber stopper in it. Remove the stopper, insert the crobar, straight end first, into the hole until it matches up with the 'screw' inside the hole & crank. The tire will eventually fall to the ground. Either pull it out or drive ur vehicle forward to expse the tire.

Here is some useless information. If u notice, the face of the tire closer to the front of the vehicle is angled down. This is a safety issue where if u were to get rear ended, the tire has no chance of going into the passenger cabin & will do little damage to the rest of the car if it is dislodged.

Underneath if you do not have run flats which in that case you have no spare.