I’ve certainly been there, so if my highest elevation is by chance not in the Rockies, it would be that.
Kala Pattar, Nepal 18,514 feet. Winter 1981.
Its the best place to get the most rewarding view of Everest, but the altitude kicks your ass.
Hiked all the way in from Lamasungu (the road ended here). This is the same route Hillary took on his way to the top.
Most people fly all the way to Lukla to save several days of difficult hiking. (Wimps!)
Just from running the cursor over the stuff in Google Earth, it looks like it was somewhere in the upper 3,000s, in Western Virginia.
Another Pike’s Peak.
17k and change at the top of Thorung La on the 'round Annapurna trek in Nepal. One gets to see 3 of the 14 8000m peaks on that trek, and let me just say that the 5400m of that pass was lots, lots high enough for me.
I tend to agree, but taking the pure route can add a number of extra days. If one is pressed for time, and acclimatize well, Lukla isn’t a bad option. I won’t hold it against them. Besides, the wild landing is interesting. It’s the often excessive use of porters that sort of has me scratching my head. I know it is good for the local economy, but on these kinds of treks you don’t need to be packing huge amounts of gear. I couldn’t believe the massive amounts of stuff some people were having their porters carry…and these weren’t the inclusive package groups or climbers, but just private parties of 2-4 people.
Kalla Pattar is awesome. I was lucky and got a clear day in the off-season. Risky, given the previous weather, but totally worth only having about six or seven people watching the sun-rise over Everest. I wanted to return to Namche via Gokyo (apparently there is a good summit view there as well) but it snowed too much and the pass was sketchy. There was a Thai expedition at Base Camp (1st Thai attempt). Apparently base camp is usually off limits to trekkers, but given the off-season and the special nature of the expedition (an attempt for the King’s 80th) they let us, gave us lunch and put us on Thai TV well-wishing the climbing team.
Speaking of Nepal…Annapurna Sanctuary is another great trek.
Another Pike’s Peak, by cog train. It was wild to start the journey at the bottom, July, HOT, get to the top and see all the snow. Very cool experience.
Just over 11,000 feet for me, climbing somewhere in Arizona. Not rock climbing; just walking around. Went up to some kind of peak that sort of just ended; it’s the one and only time I’ve ever felt the actual effects of less-oxygen-than-you’re-used-to, and that’s including time spent in non-airtight-planes. 
Mount Mitchell, NC - 6,684ft
Yet another one for Mt. Evans. I was about 10 years old, and couldn’t get out of the car, I was so dizzy. We spent about 5 minutes at the turn out at the top, and went back down to Denver. The headache that night was memorable.
Pike’s Peak (via the cog railway) would be the highest we’ve been on land. A few days later, we drove Trail Ridge Road, which is 12,000+ feet high.
About 7000 feet above sea level in the Chisos mountains of Big Bend park, Texas.
10,000 - 15,000 a number of times in Wyoming and Colorado.
I am thinking of doing the trek to Everst base camp next spring though. I think that’s about 17,600 and there may be a pass or two that are higher that you have to cross getting there.
Oops. Here’s to screwing up your poll through lack of memory and research! 
Probably the result of the altitude…
Mt Kinabulu (13,435 feet) - the highest mountain in SE Asia in Sabah, Malaysia specifically on the island of Borneo.
A pretty easy trekking peak albeit it more difficult in some short sections lower down if there have been recent rains. Sleepless night in a trekking lodge before an early rise to experience dawn on the summit, with the sun rising through the clouds below you.
Pretty good memories - about 15 to 20 years ago now.
Mt. Denali, Alaska. 20,320 feet. Many years and many pounds ago.
The Jungfrau (13,642) was much easier, as was the Shilthorn (9,744). You just ride the train! (Or tram)
My grandfather was a consummate outdoorsman, and he insisted on climbing the highest peak in every state we’d visit. I’ve done them all, except Hawaii.
Hiked up to over 14k in the Rwenzori range in Uganda.
7,265 ft. at Crater Lake, Oregon, and I had a headache from it.
Long’s Peak, twice.
The first time was about 1979. The plan was to do a grade II technical climbing route from the lake up to Broadway and then another grade II up the left edge of The Diamond to the top. A grade II is supposed to require half a day, so we thought we could get two of them done in one day.
The start in the early morning hours was scary. People who had bivouacked overnight on Broadway were kicking pebbles and rocks off of Broadway frequently, and by the time they reached our vicinity they were traveling at terminal velocity. We didn’t have helmets.
We reached the summit after the sun had set, too late to rappel down. Spent a restless, chilly night looking up at an incredible Milky Way. We were extremely fortunate at the lack of wind and clouds.
The second time, in late August of 2008, was lots more fun. We went on a weekend which all the weather forecasters agreed would be clear and nearly windless. My partner had been turned back by weather 6 times previously. We planned to do the easiest route as described in previous posts. We got what would ordinarily be considered a late start but guaranteed good weather made lattes and the funnies prior to departing the parking lot a viable option.
As we got closer to the mountain more of the people passing us on their way back to the parking lot were making comments like “you guys are kinda late, aren’t you?” and “you’ll still be on the trail after dark”. We got tired of it and and started offering rejoinders such as “we have two hits of acid and some kind bud, we’ll be alright.” Of course what we really had was headlamps, plenty of food and water, and some kind bud. For those of you who don’t know, “kind bud” is the kind to have.
The peak was fantastic. We had it all to ourselves except for a marmot which was looking for a handout. Damned liberal marmot I betcha.
As we started the descent I heard a whistling noise which I at first thought might be an eagle or other big bird. Big and birdlike it was- a glider was circling the peak, apparently with a whistle built into the tail.
We got back to the parking lot after dark, well satisfied with the experience.