Flagstaff Road is the climb in Boulder.

Flagstaff Profile

Length: 4.55 miles (7.32km)
Average Grade:
Maximum Grade:
Vertical Gain:
2060 ft (628m)
Summit: 7700 ft (2347m)
Tour de France Category:
Tour de France analogue:
– Final climb, Stage 14, 2010 TdF

There is usually light traffic on this road.  It is mostly used by locals who live in the mountains (traffic down in the morning, up in the evening), and by tourists.  However, the road is narrow with no shoulder.

Baseline Road, named for its exact 40 degrees north latitude, heads west from Broadway past Chautauqua Park and the famous view of the Flatirons.  The climb is usually measured from the right turn across the stone bridge where Baseline becomes Flagstaff Road.

The climb starts abruptly and the first mile up to the overlook is very steep with the first mile averaging 8.6% grade.  After the Flagstaff House Restaurant the grade eases somewhat for a second mile at 5.5%.  There are two more tight switchbacks and then a flatter section leading to the final push to the amphitheater turnoff.  The third mile to the turnoff is 6.1%.

Above the Amphitheater

Most people turn right and follow the gentler climb for about 1/2 mile to the amphitheater overlook.  Those in the know understand the climb has barely even started.  The 1.5 miles beyond ascend as many vertical feet as the 3 miles to the turnoff.

The fourth mile averages 10.8% grade, and 12.8% for 3/4 mile.  There is a brief respite as you pass the Panorama Overlook, but you quickly reach the final, steep switchbacks with the final 0.5 mile averaging a cool 9.9% grade.

Some choose to descend the backside until the road turns to dirt (“Where the sidewalk ends”) and turn around there.  Either way, enjoy your descent!

The final switchback

9 Responses to Flagstaff

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  2. Jason says:

    Any idea your time up flagstaff? And also if you timed yourself coming back down? New to boulder and have ridden flagstaff a few times.

    • says:

      I’ve been using Flagstaff as a benchmark so I know my times well. My best time was 27:32 on March 31. This is timed from Gregory Canyon to the “Leaving Mountain Parks” sign at the summit. My time to the Amphitheater split on that run was 14:30, which is where most people stop. The road is much steeper after the Amphitheater split to the top.

      I’ve never timed myself on the way down since I’m not ‘racing’ myself, but I do like to go fast. I looked at my PowerTap data and it looks like on that day I descended in 9:06, averaging 30.2 mph and a max of 46.

  3. Jason says:

    Thanks for the quick reply!! Awesome blog and I will head out today and see how fast I get to the top. :) Past the Amphitheater is where the “real climbing” starts. Hope the races go well this weekend.

  4. Chris says:

    I’m a rider from the flat lands of Iowa and just moved to Denver. Love the Colorado climb sections.. keep it up! Just out of curiosity, I did Lookout Mt. with a 11-21 cassette but wasn’t happy about it. What gear setup do you have for Flagstaff?

    Thanks again for all the info. Super interesting while watching the tour and comparing climbs.

    • says:


      I usually ride a 12-25 for winter training when I stay on the plains. When spring comes around I’ll switch to a 12-27, which is pretty good for flagstaff.

      The larger ratio cassettes allow for a reasonable cadence when the grade is over 8%, and I find I can stay in the big ring on the flats, since I can push my 53-21 without a bad chain line.

      Most recreational riders in Colorado will be best served by a compact crankset (50-34) and a 11-27. The 11T is essential on a compact, and for racing. SRAM seems to understand this, as their Red cassettes only come in an 11T on all four available ratios.

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