Deep Cut Guide

Rattler Boulders

1 boulder problem · Ash-flow tuff of main volcanic sequence · 8,339 ft

Help locate these routes: survey the wall

How well located

Crag only 1 

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

Rock, from the geologic map

Ash-flow tuff of main volcanic sequence — volcanic. Cenozoic, about 34 to 23 million years old.

Includes many named units

This is the map unit under this crag's map point, read from the 1:500,000 sheet (Horton and others, 2017, U.S. Geological Survey Data Series 1052). 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 500 m wide on the ground, so the wall itself may be the neighbouring unit. Every crag on this unit: Ash-flow tuff of main volcanic sequence. Geology data: Macrostrat (CC BY 4.0), serving USGS and Colorado Geological Survey maps.

On the map since 1915

The USGS has mapped this ground since 1915. 19 historical sheets cover this crag's map point; the oldest is below.

Thumbnail of the 1915 USGS sheet covering Rattler Boulders
USGS 1:125000-scale Quadrangle for Del Norte, CO 1915 · U.S. Geological Survey · 1915 · 1:125,000 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, 1915 to 2001: USGS topoView.

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.

Entrance to Sah Watch valley. San Luis valley and the Sierra Blanca in the distance · P.S. Duval & Co. · 1854
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.

Community building. San Luis Valley, Colorado · Rothstein, Arthur, 1915-1985 · 1939
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.

Community building. San Luis Valley, Colorado · Rothstein, Arthur, 1915-1985 · 1939
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.

Dairy herding on alfalfa. San Luis Valley, Colorado · Rothstein, Arthur, 1915-1985 · 1939
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.

Farmstead on San Luis Valley Farms, Colorado · Rothstein, Arthur, 1915-1985 · 1939
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.

Farmstead. San Luis Valley Farms, Colorado · Rothstein, Arthur, 1915-1985 · 1939
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.

Farmstead. San Luis Valley Farms, Colorado · Rothstein, Arthur, 1915-1985 · 1939
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.

Grain harvest, San Luis Valley Farms, Alamosa, Colorado · Rothstein, Arthur, 1915-1985 · 1939
Library of Congress, Prints & Photographs Division · Public domain · the record · found by place name, not yet checked
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Hidden as soon as you tell us, everywhere it appears, before anyone reviews it.

Grain threshing outfit in operation on San Luis Valley Farms, Colorado · Rothstein, Arthur, 1915-1985 · 1939
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.

Mr. and Mrs. Howard Crowder and daughter on their resettlement farm. San Luis Valley, Colorado · Rothstein, Arthur, 1915-1985 · 1939
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.

12 more at the Library of Congress.

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 08:40-14:00
Wall faces SE (USGS elevation). Shade from the surrounding terrain is counted.
Partly enclosed: the skyline averages 8° above horizontal.
Rain & forecast
No recent weather for this crag.

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 37.59733 N, 106.31416 W (Rattler Boulders). That point can be off by hundreds of metres, so say so.

The map point for this crag is on land managed by Rio Grande National Forest (federal). It lies inside national forest.

The boundary is close. Land managed by Bureau of Land Management comes within 250 m of this point, and the point is not the rock — the wall itself may be on the other side of the line. Check which before you rely on either one's rules.

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.

Nobody has yet read Rio Grande National Forest's own rules for this crag and written them down here, so treat the above as where you are, not as what you may do.

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