Northeast corner of Colorado

According to the Congressional definition of the boundary of Colorado, this point is theoretically where the 41st parallel north latitude intersects 25 degrees west longitude as measured from the Washington Meridian*. However, this monument was first set by Oliver Chaffee during his 1869 survey - and due to the technological limitations of his day, it's not exactly right (although his survey does define the official boundary, regardless of its accuracy).

* Many American surveys between 1850-1884 were based on this meridian, which was officially abolished by Congress in favor of the Greenwich Prime Meridian in 1912. "25 degrees west of Washington" is a few miles away from the 102nd degree of longitude west of Greenwich.

NOTE: The book "Colorado Mapology" (Erl H. Ellis, 1983, Jende-Hagan Book Corporation) is an excellent resource, from which I obtained much of the information presented on these pages.

The original limestone marker is broken; the photo below shows the condition of the monument in 1969:

That was looking eastward (photo by Erl Ellis, published in the reference above). From about 1972-1979, improvements were made to this site. What's left of the base is now preserved in the middle of a concrete apron and a fence enclosure, shown in the photo below.

Fall 1993

In that shot, I am standing at the northeast corner of Colorado, pointing down the north and east statelines. The view is northeast into Nebraska; that's the South Platte River valley behind me.

Page created in 1998; last updated 03 March 2003.