If anyone is curious on what the absolute limit of human endurance is for a completely self supported hike, I'd say it's about 624 miles.

http://www.ryanjordan.com/2006_arctic/

These guys were covering up to 40 miles a day in some pretty tough terrain.

Ha, ha! I've hiked with Ryan! He's certifiable. I'm a lightweight hiker, but he's what we refer to as psycho-light. If you can, find his blog post about going into the Yellowstone backcountry in winter with a 9-pound pack (including food). On that very 19-mile, 9000' day in the Tetons, I was chasing Ryan Jordan and Glen Van Peski (of gossamergear.com). The next morning I started out at their pace, but when I saw Ryan trail-running up out of a steep valley with a full pack, my quads out-voted me and I slowed down.

We had a little weigh-in before that trip, and, if I remember correctly, Glen had a 12-pound pack for a 5-day, 4-night, 75 mile trip down the west side of the park, crossing over the continental divide three times. That included food. He'd done a little scientific calculation, and determined that macadamia nuts were the best food for the weight. The upshot of that was that by day 3 he was willing to trade almost anything to get something else to eat.

That was a damn fun trip. It was 9 days after September 11th, 2001, which made the flight out very exciting. Yellowstone was empty, though, when we went up there on our 'acclimatize day,' and we stood at Old Faithful on a beautiful September Saturday almost alone.

Macadamia nuts are almost pure fat. I like them a lot, but yes, you can get too much of them. Pemmican would've been a far better choice.

If you knew what you were doing, I'd say there is no limit on how far you can go on a self supported hike. It depends on how much you would rely exclusively on what you bring. A good naturalist ought to be able to go for weeks on end, and cover over a thousand miles. I believe there was a story of a pair of hunters back in the 1800s that lived off of buffalo while they crossed the dakotas and half of Minnesota afoot, their horses being "borrowed" by a local tribe at the time. Of course you couldn't do that now, but there was a time when living off the land while travelling was a lot easier and more commonplace.

If you can make 2Km / 1.6 Miles per hour you are doing well in poor terrain with out trails etc. Add in another hour for each 300m / 1000' elevation gained and remember that groups cannot usually make more than 8 hours a day hiking unless they train for it.

Well, considering I got this on TV, it must be flavored with the ubiquitous grain of salt...

During lunch today, I saw a special on the USAF PJ's. They were showing part of their final FTX at the end of their 2 year school. It stated they were going to be covering 60 miles per day in full gear.

I saw their packs, I remember what those things weigh. If they were doing 60 miles per every 24 hours, they were not going to maintain that for very long without resupply of water. The area was desert around Kirtland AFB (Desert South West) New Mexico.

EDIT: They wouldn't be doing 60 miles per day for very long anyway if at all.

Having trained with the DOE not far from there for two weeks, I know the area. Water was not one of the elements that was readily available when the maker created this place. It was obviously already used up.

Is 60 miles in one day possible, yes. Is it possible for me in the sad shape I have allowed myself to get into, OH NO! [expletives deleted in advance]

This is a subject Montanero can probably relate experiences to. I am absolutely sure he has more time in varied terrain than several of us combined and multiplied by the same number.

This wasn't on the Discovery Channel by any chance. It would explain a lot about that claim. If this is correct then this is truly remarkable effort. I seem to remember reading somewhere that the Green Berets physical requirements for hill fitness being roughly half this distance per day.

I try to make sure they are chocolate covered, for a more balanced diet

Whew, I don't know anything about the terrain or those guys' fitness (though I'm sure they're in awesome shape) but 60 miles per day does sound extreme, close to impossible.

If you look at Bravo Two Zero, the SAS patrol at one point completed about two consecutive marathon runs in 24 hours while Ryan covered 190 miles in 8 days altogether. Granted, it was under combat conditions but the sheer exertion nearly cost him his life and left him partly crippled for life.

Anyway, I'm not sure 60 miles in a single day is feasible even for the best trained guys, let alone as an average for several consecutive days. Maybe the TV editor just made a mistake somewhere?

My point exactly

A very good friend of mine is a PJ- way I heard it from him was 60km. Still a good haul on broken ground and with full kit, but doable if you aren't (a) worried about setting camp, (b) know you can crash shortly after you get there, (c) prep for it, and (d) are trained that hard. But you can't do it for a prolonged period.