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100 years of US routes: 1926-2026
(referred to as Corner C on this page)
According to the Congressional definition of the boundary of Colorado, this point is theoretically where the 41st parallel north latitude intersects 27 degrees west longitude as measured from the Washington Meridian*. This monument was first set by Oliver Chaffee during his 1869 survey, and due to the technological limitations of his day, it is not exactly right (although his survey does define the official boundary, regardless of its accuracy).
*Many American surveys between 1850-1884 were based on the Washington Meridian, which was officially abolished by Congress in favor of the Greenwich Prime Meridian in 1912. "27 degrees west of Washington" is a few miles away from the 104th degree of longitude west of Greenwich.
This photo was looking east; the cross ties on the fence enclosed the southeast corner of Wyoming:
Ellis, 1969
Improvements were made to this site in 1981 -- for one thing, as of 1992 there was a diagonal easement in the southeast corner of Wyoming:
Sanderson, Aug. 1992
The camera was in Colorado, looking northeast. I was standing in the southwest corner of Nebraska's panhandle. My lovely wife was in the southeast corner of Wyoming. The fence runs along the east and south Wyoming state line.
Reportedly in 1869 Chaffee surrounded the original marker with a huge mound of stones, so it is possible that the rocks strewn around the site today are remnants from that pile.
Here is a closeup of the marker. It is one of the better ones I have seen: the original marker is preserved in the center, with a USGS benchmark on top. The new base is a "map" fashioned out of a type of rock commonly found in each respective state: red Lyons Sandstone for CO, black slate for WY, and buff sandstone for NE:
Sanderson, Aug. 1992
Additional improvements were made in 1997; this photo was taken looking northwest:
Morrison, Aug. 2016
Visible at far left is an interpretive plaque; the text is shown close-up here:
Morrison, Aug. 2016
In 1992, I thought the stone "map" on the base was in pretty good shape, but maybe it was damaged between then and 1997. At any rate, it is now covered with a black metal plate:
Morrison, Aug. 2016 (looking south)
Morrison, Aug. 2016 (looking west)
Research and/or photo credits: Erl Ellis; Jeff Morrison; Dale Sanderson
Page originally created 1998;last updated Dec. 14, 2025.
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