Deep Cut Guide

Upper Y Traverse

1 route and 17 boulder problems · sandstone (Fountain Formation) · 6,480 ft

Take me there Routes ↓ Directions

Help locate these routes: survey the wall

What's here

VB to V7, mostly around V1.

  1. 1 VB
  2. 7 V1
  3. 5 V3
  4. 3 V4
  5. 1 V7

Counted from the 17 climbs here that carry a grade. Shown only where there are at least 5 of them — below that the shape is noise.

How well located

Position on wall known 15  Crag only 3 

No route here has its own point yet. The map pin is the crag. At the wall? Survey it: 30 seconds per route.

The order of the climbs along this wall is known from the open catalogue, so a few surveys go a long way: standing at High Traverse, Pinch Bulge Sit Down, Thin Crimp Bulge (3 climbs, about 90 seconds) would place up to 12 more climbs between them. Survey the wall →

“Up to” because the estimate between two surveyed routes is only used when they turn out to be close enough together on the ground.

The guidebook for this area

Colorado Bouldering: Front Range - Phillip Benningfield, Matt Samet - 2020 every crag it covers

From the publisherBookshop.org

Bookshop.org links are affiliate links: if you buy through one we earn a commission, at no extra cost to you. Bookshop.org gives its profits to independent bookshops.

The book has the topos, the descriptions and the local knowledge this page can't. Buying it helps support the people who know the crag best.

Rock, from the geologic map

Rhyodacite And Basalt. Paleocene, about 66 to 56 million years old.

Rhyodacite in sills between Lyons and Boulder is light-gray, very fine grained felsite and felsite porphyry. Sills are as much as 46 m thick, but most are about half that. Radiometric age (Larson and Hoblitt, 1973, p. 3) of Flagstaff Mountain sill is 64.

This is the map unit under this crag's map point, read from the 1:100,000 sheet (Colton, Roger B., 1976, U.S. Geological Survey Geologic Investigations Series I-855-G). The point can be a few hundred metres from the rock, a cliff often stands on the line between two units, and at that scale a line on the map is about 100 m wide on the ground, so the wall itself may be the neighbouring unit. The rock named at the top of this page comes from the public geology of this area; this card is the map's answer. Every crag on this unit: Rhyodacite And Basalt. Geology data: Macrostrat (CC BY 4.0), serving USGS and Colorado Geological Survey maps.

On the map since 1902

The USGS has mapped this ground since 1902. 29 historical sheets cover this crag's map point; the oldest is below.

Thumbnail of the 1902 USGS sheet covering Upper Y Traverse
USGS 1:62500-scale Quadrangle for Boulder, CO 1902 · U.S. Geological Survey · 1902 · 1:62,500 sheet
USGS Historical Topographic Map Collection · Public domain · the record · placed by its coordinates
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Hidden as soon as you tell us, everywhere it appears, before anyone reviews it.

Public domain, U.S. Geological Survey. The sheet shows the ground as the survey found it then, which is why a trail or road you know may be missing. Every sheet over this point, 1902 to 1984: USGS topoView.

In print since 1877

  • 1877 Geologic Map of Colorado (Hayden), high-resolution scan · F. V. Hayden; scan by the Colorado Geological Survey · 1877

    The whole-state sheet of the 1877 atlas, scanned at full resolution by the state survey and free to download.

    Colorado Geological Survey (publication HM-01-04) · Public domain · read it

  • Geological and geographical atlas of Colorado and portions of adjacent territory · F. V. Hayden, U.S. Geological and Geographical Survey of the Territories · 1877

    The first geology anyone drew of this ground. Hayden's survey mapped the state in the 1870s; these are the sheets, with the rock units coloured as they understood them then.

    Internet Archive (Brigham Young University copy) · Public domain · read it

  • Trail and Timberline, volume 2 (1918) · Colorado Mountain Club · 1918

    The Colorado Mountain Club's own magazine in its sixth year, with the club's outings and ascents as its members wrote them up at the time.

    Internet Archive (Brigham Young University copy) · Public domain · read it

Free to read: public domain or government work. About Boulder as a whole, not this wall. More in the reading room.

From the archives

Photographs of this area held by the Library of Congress, oldest first. Every one carries the Library's own "no known restrictions on publication"; anything else is left out.

Boulder, Colorado
Boulder, Colorado · Detroit Photographic Co. · 1900 · photochrom
Library of Congress, Prints & Photographs Division · Public domain · the record · indexed to this place by the archive
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Boulder Falls, Boulder Canyon, Colorado · 1903 · postcard
Library of Congress, Prints & Photographs Division · Public domain · the record · indexed to this place by the archive
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Hidden as soon as you tell us, everywhere it appears, before anyone reviews it.

Chautauqua Grounds, Boulder, Colorado · 1903 · postcard
Library of Congress, Prints & Photographs Division · Public domain · the record · indexed to this place by the archive
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The perfect tree, Boulder Canon, Colo. · 1906 · stereograph
Library of Congress, Prints & Photographs Division · Public domain · the record · indexed to this place by the archive
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South Boulder Valley, Colorado · 1907 · postcard
Library of Congress, Prints & Photographs Division · Public domain · the record · indexed to this place by the archive
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Birds eye view of Boulder, Co. · Haines Photo Co. (Conneaut, Ohio) · 1908
Library of Congress, Prints & Photographs Division · Public domain · the record · indexed to this place by the archive
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Boulder, nestling between mountain and plain, Colorado · 1908 · stereograph
Library of Congress, Prints & Photographs Division · Public domain · the record · indexed to this place by the archive
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Overlooking the little city of Boulder, Colorado · 1908 · stereograph
Library of Congress, Prints & Photographs Division · Public domain · the record · found by place name, not yet checked
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A peep at Boulder, Colorado · 1909 · stereograph
Library of Congress, Prints & Photographs Division · Public domain · the record · indexed to this place by the archive
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Boulder Park, Colo. "Moffat Road" · 1909 · postcard
Library of Congress, Prints & Photographs Division · Public domain · the record · indexed to this place by the archive
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2 more at the Library of Congress.

Photographs near this crag

Taken within 1.5 km of this crag's map point and published under a licence that lets us show them, from Wikimedia Commons. The coordinates say where the camera was, not what it was pointed at, so some of these will be the creek or the trail rather than the rock.

Boulder Canyon (9712361910)
Boulder Canyon (9712361910) · Akos Kokai · 2013 · 126 m from the crag's map point
Wikimedia Commons · CC BY · the record · placed by its coordinates
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The Flatirons from the Chautauqua Park - panoramio · hakkun · 2007 · 1,037 m from the crag's map point
Wikimedia Commons · CC BY-SA · the record · placed by its coordinates
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Sunrise on Flagstaff Mountain · Jacob Dong · 2018 · 1,213 m from the crag's map point
Wikimedia Commons · CC BY-SA · the record · placed by its coordinates
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Opuntia sp. (9712353548) · Akos Kokai · 2013 · 43 m from the crag's map point
Wikimedia Commons · CC BY · the record · placed by its coordinates
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Rocks (9709120923) · Akos Kokai · 2013 · 43 m from the crag's map point
Wikimedia Commons · CC BY · the record · placed by its coordinates
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Mountain weather (9709127439) · Akos Kokai · 2013 · 175 m from the crag's map point
Wikimedia Commons · CC BY · the record · placed by its coordinates
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CUにかかる月 Moon over CU (8168666686) · Yuya Sekiguchi · 2010 · 362 m from the crag's map point
Wikimedia Commons · CC BY · the record · placed by its coordinates
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PXL 20211230 204354467 (51802834383) · Jack from Boulder, Colorado, U.S. · 2021 · 373 m from the crag's map point
Wikimedia Commons · CC BY-SA · the record · placed by its coordinates
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PXL 20211230 204354467a (51802712781) · Jack from Boulder, Colorado, U.S. · 2021 · 373 m from the crag's map point
Wikimedia Commons · CC BY-SA · the record · placed by its coordinates
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PXL 20211230 204357357 (51803437380) · Jack from Boulder, Colorado, U.S. · 2021 · 373 m from the crag's map point
Wikimedia Commons · CC BY-SA · the record · placed by its coordinates
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PXL 20211230 204150323 (51803437075) · Jack from Boulder, Colorado, U.S. · 2021 · 374 m from the crag's map point
Wikimedia Commons · CC BY-SA · the record · placed by its coordinates
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PXL 20211230 204202124 (51801762807) · Jack from Boulder, Colorado, U.S. · 2021 · 374 m from the crag's map point
Wikimedia Commons · CC BY-SA · the record · placed by its coordinates
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17 more on Commons.

Routes

Also within 3 km

Straight line between the two crags' map points, each of which can be some way from its rock. For when this wall is full, or the sun has found it.

Photos from climbers

No photos here yet. If you're at the crag, yours would be the first.

Pick a photo from your camera roll rather than taking one here: a picture taken inside a browser usually has no location saved in it, and we check that the photo was taken at this crag before publishing it. Photos of guidebook pages and topos are refused — they're the author's work. By sending one you're letting us publish it.

Nobody reviews these before they appear, so anyone can report one and it's hidden straight away — including you, if you change your mind, and including a photographer who finds their own picture here.

Taken at the crag by climbers and published as they sent them. Each one's own location had to be within 0.5 km of this crag before we accepted it. See something that shouldn't be here? Use Report this photo under it and it's hidden at once. Anything else, write to us.

Sun today
sun 07:20-11:20
Wall faces E (USGS elevation). Shade from the surrounding terrain is counted.
Partly enclosed: the skyline averages 10° above horizontal.
Crags by sun and shade →
Rain & forecast
0 mm of rain in the last 48 hours.
11-11 56°/43° · 0.0 mm · 18 mph · pm storms 0% 11-12 56°/44° · 0.0 mm · 8 mph · pm storms 0% 11-13 58°/40° · 0.0 mm · 9 mph · pm storms 0%
Open-Meteo, fetched 2026-11-11 18:40 UTC

Conditions reported

Nothing reported recently.

Report what you see

Reports are dated and fade on their own: wet rock after 3 days, a bad bolt after a year. No names, no text.

Access & safety

Emergency: call 911. Read out your location: Works without signal. If GPS fails, this crag's approximate map point is 40.00353 N, 105.29773 W (Upper Y Traverse). That point can be off by hundreds of metres, so say so.

The map point for this crag is on land managed by City of Boulder Open Space and Mountain Parks (local government), in State Patent - Panorama.

Land manager from USGS PAD-US (public domain), read 2026-09-29. It is the manager of the crag's map point, which can be a long way from the wall. What you may do on the rock is the manager's to say, not ours.

Rules for all City of Boulder Open Space and Mountain Parks land

Fees
Parking fees apply at certain trailheads for vehicles not registered in Boulder County.
Permits
Off-trail permits are required to reach some climbing areas inside Habitat Conservation Areas.
Climbing permit
It is illegal to place fixed protection without a permit. Replacement and new bolted routes go through the Flatirons Climbing Council application, decided by OSMP.
Rules
Climbing gear -- ropes, webbing, slings, quickdraws -- may not be left unattended. Grooming, tree cutting, rock gluing and chipping are prohibited. Drones are prohibited. Seasonal raptor closures run 15 December to 31 July depending on species.
Overnight
Camping is prohibited on Open Space and Mountain Parks, as are tents, nets and other structures. The exception is Buckingham Campground at Fourth of July Trailhead.
Dogs
All dogs must be leashed unless the dog and its guardian are registered in the Voice & Sight Tag Program, and off-leash dogs must display the city's V&S tag and rabies tags.

Read on City of Boulder Open Space and Mountain Parks's own pages, checked 2026-09-29 by John Crawford. What they require, in full, or their own climbing page. These apply to the manager's whole holding; anything specific to this crag is above.

Nearby, from OpenStreetMap

Toilets
378 m away (map)
Mapped parking
84 m away (map)

Distances are a straight line from this crag's map point, which can itself be hundreds of metres off; a road may be much longer. Mapped by OpenStreetMap contributors (ODbL), so a toilet missing here may simply be unmapped. Parking here is what OSM has drawn nearby, not a guidebook's directions.

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