Racing at altitude when you don't live there

The high ones, and what is on the calendar

This is the list a race directory never has to make: places people travel to, that also happen to be high. Breckenridge is the highest we cover at about 9,600 ft.

Destination	Height	Races listed
Breckenridge, CO	9,600 ft	5
Mammoth Lakes, CA	8,250 ft	—
Vail, CO	8,250 ft	4
Aspen, CO	7,950 ft	3
Park City, UT	7,150 ft	29
Taos, NM	6,950 ft	1
Steamboat Springs, CO	6,850 ft	5
Flagstaff, AZ	6,850 ft	4
Santa Fe, NM	6,750 ft	6
Durango, CO	6,550 ft	6
Colorado Springs, CO	6,350 ft	28
Lake Tahoe, CA	6,250 ft	3
Jackson, WY	6,150 ft	1
Sun Valley, ID	6,050 ft	—
Cheyenne, WY	6,050 ft	2
Denver, CO	5,300 ft	151
Boulder, CO	5,250 ft	53
Fort Collins, CO	5,000 ft	30
Albuquerque, NM	4,950 ft	32
Reno, NV	4,950 ft	13
Bozeman, MT	4,800 ft	8
Sedona, AZ	4,350 ft	4
Salt Lake City, UT	4,200 ft	36
Moab, UT	4,050 ft	1
El Paso, TX	3,900 ft	42
Bend, OR	3,650 ft	10
Rapid City, SD	3,400 ft	1
Billings, MT	3,200 ft	9
Missoula, MT	3,150 ft	5
Whitefish, MT	3,050 ft	4

Heights are measured at the town centre. Race counts are everything on our calendar within 25 miles, read from the database when this page's server last restarted — so they move as the calendar does. Six of our destinations name a region rather than a town (the Outer Banks, Door County, Martha's Vineyard, Lake Tahoe, Maui, Kona); those are measured at a named town inside them, and none but Lake Tahoe is high enough to appear above.

What altitude actually does

Thinner air carries less oxygen, so the ceiling on how hard you can work aerobically comes down. The clearest measurement of it is Wehrlin and Hallén (2006), who put eight endurance-trained athletes in a hypobaric chamber at six simulated altitudes: VO₂max fell about 6.3% for every 1,000 m of altitude — roughly 1.9% per 1,000 ft — and it fell in a straight line, with no threshold below which nothing happened. It was already measurable between 300 m and 800 m.

Two things follow that are worth having. The effect arrives on the day, not after a bad week: it is the air, not your training. And it does not care how fit you are — the athletes in that study were the fit ones.

We will not give you a pace adjustment

Every altitude calculator on the internet will convert a height into a predicted finishing time, and most of them are built on the number in the paragraph above. That number is a laboratory VO₂max decline in eight people. Your 10K on Saturday is not a chamber test, and the arithmetic between the two runs through your event, your pacing, the course, the temperature, how you slept and how you personally respond to hypoxia — which varies enormously between people and is not predictable from anything you could type into a box.

So this site tells you how high the place is and points you at the measurement. Anything past that would be a number with a decimal point on it and nothing behind it, which is the one thing we try hardest not to publish. It is the same reason a walk to the start line is described as about a twenty-minute walk rather than 0.83 miles.

A town's height is not a race's height

The number beside a destination is measured at the town centre, and a race twenty miles up a canyon is not at the town centre. We measured every race we hold near the high destinations at its own coordinates, and in mountain country the two come apart hard:

Park City, UT — the town is about 7,150 ft, and the 28 races we list within 25 miles run from about 4,200 to 9,550 ft.
Salt Lake City, UT — the town is about 4,200 ft, and the 37 races we list within 25 miles run from about 4,200 to 9,550 ft.
Flagstaff, AZ — the town is about 6,850 ft, and the 5 races we list within 25 miles run from about 4,550 to 8,300 ft.
Breckenridge, CO — the town is about 9,600 ft, and the 4 races we list within 25 miles run from about 9,500 to 13,200 ft.
Colorado Springs, CO — the town is about 6,350 ft, and the 28 races we list within 25 miles run from about 5,350 to 9,050 ft.
Reno, NV — the town is about 4,950 ft, and the 12 races we list within 25 miles run from about 4,400 to 7,400 ft.

That is why a result page says the range as well as the height whenever the range is wide, and why neither number is ever attached to an individual race. We know where a race starts; we have not measured how high its start line is.

Above 8,200 ft it stops being about pace

Altitude illness is a medical subject and we are not going to paraphrase one. The CDC's guidance is the thing to read, and it draws its line at 2,500 m — about 8,200 ft — with symptoms typically arriving 6 to 12 hours after you get there and being worst after the first night.

CDC: High-Altitude Travel & Altitude Illness. A handful of our destinations are above that line, and a race there is a different kind of decision from a race at 5,000 ft.

Where these numbers come from

Heights are from the USGS Elevation Point Query Service (3DEP), which is free, keyless and public domain — the same kind of source as the Census geocoder this site already runs on. They were measured on 3 September 2026 and checked in, because the ground does not move and a lookup on the request path would only add a way for a fact to fail.

Race counts and the corpus figures are read from the database at every restart. How this works has the rest, and the tips page has what 8,853 races say about fitting a run into a trip you have already booked.