The White Mountains please help!?

where do i begin i need help so badly i have 7 different tabs up and basically im trying to figure out where the white mountains are if they aren't even mountains just a saying and theres all different mountains, where the kancamangus highway begins and ends not like just the towns like literally, like where the top of it is and where the bottom of it is, i went on a car cruise and im so confused on where we went we were on the kancamangus highway but obv. didnt make it to the top all we did was start from the bottom and go to loon mountain and then back here to boston i just remember after loon mountain we left to go home stopped at a little conveient store and i remember looking straight ahead and seeing a road going wayyyyy up and wondering if that would have kept going to the top, im so confused please help with detailed answers i just want to know where it is what it is and all that!