Knowing the volume of the reserve tank is important to avoid running out of gas on the road! Jeep hasn’t published any concrete details of how far their vehicles can drive on empty, but generally speaking a Jeep can go about 30-45 miles on empty before needing to add gas to the tank.
As a general rule, the empty fuel tank warning light will illuminate when your gas tank is at about 10-15% capacity, which means that if your car gets about 300 miles per tank, you could probably drive about 30-45 miles on empty before running out of fuel. However, the distance may differ based on what Jeep model you drive.