A permit is required for hiking the Mount Whitney trail and for any hikes in the Mount Whitney Zone, which includes the Mountaineers Route. Between May and November, there is a quota of 100 hikers per day. There are an unlimited number of permits available for the winter months. The Mount Whitney permit lottery begins in February and it is all permits are given out during that time. The Whitney Portal store's online message board has posts for hikers with extra openings on their permits.
For more information, or to apply for a wilderness permit, visit http://www.fs.fed.us/r5/inyo/recreation/wild/permitsres.shtml
It's a good idea to visit Whitney Portal during the day and get to know the layout before attempting the hike. If you're camping at the Portal you'll have plenty of time to do this. If you're staying down in Lone Pine or elsewhere, I'd recommend driving up and get to know the lay of the land. It will likely be dark when you arrive to start the hike so it will make it easier if you know beforehand where you will park, where the bathrooms are, and most importantly, where the trail head is. We did not do this and as a result we probably wasted 30 minutes just wandering around in the dark looking for the trail head.
And while you're here you can visit the Portal Store, purchase some last minute supplies, and get a bite to eat.
Fondest memory: Dark, very dark!
Because of it popularity among hikers and backpackers, the National Forest Service limits the number of hikers/backpackers via a permit system in order to limit the damage inflicted on the mountain and environment. Daily limits are 100 day hikers and 60 overnight campers. Permits are issued via a lottery held in February. Any remaining spots after the lottery can be obtained by inquiry to the NFS. There are associated fees per person to be hiking on a given permit.
For all the info on how to obtain a permit, go to the NFS website:
Fondest memory: Reaching the summit after 10.5 hours of hiking!