<p>This is a map of Colorado counties as they appeared until November 15, 2001, when <a href="https://en.wikipedia.org/wiki/Broomfield_County,_Colorado" class="extiw" title="w:Broomfield County, Colorado">Broomfield County</a> was created from portions of <a href="https://en.wikipedia.org/wiki/Adams_County,_Colorado" class="extiw" title="w:Adams County, Colorado">Adams</a>, <a href="https://en.wikipedia.org/wiki/Boulder_County,_Colorado" class="extiw" title="w:Boulder County, Colorado">Boulder</a>, <a href="https://en.wikipedia.org/wiki/Jefferson_County,_Colorado" class="extiw" title="w:Jefferson County, Colorado">Jefferson</a> and <a href="https://en.wikipedia.org/wiki/Weld_County,_Colorado" class="extiw" title="w:Weld County, Colorado">Weld</a> counties.
This map uses <a href="https://en.wikipedia.org/wiki/azimuthal_equidistant_projection" class="extiw" title="w:azimuthal equidistant projection">azimuthal equidistant projection</a>, centered on (−105.7167, 39.1333) (degrees latitude, longitude).  The area outside Colorado is transparent, so it should look nice on non-white backgrounds.
</p><p>The data I used is apparently accurate to 0.000278 degrees, or about 100 feet.  The coordinates in this map are in decameters.
</p>
This map is probably not eligible for copyright.  Just in case, I release my own contributions to the public domain.
<a href="//commons.wikimedia.org/wiki/User:Dbenbenn" title="User:Dbenbenn">David Benbennick</a>
Own work  using: <a rel="nofollow" class="external text" href="http://nationalatlas.gov">nationalatlas.gov</a> County Boundaries, 2000 data set, specifically <a rel="nofollow" class="external text" href="https://edcftp.cr.usgs.gov/pub/data/nationalatlas/co2000p020.tar.gz">co2000p020.tar.gz</a>.  I used <a rel="nofollow" class="external text" href="http://www.geo.unizh.ch/~uruetsch/software/shpdump.html">shpdump</a> to extract the Shapefile.  See <a href="//commons.wikimedia.org/wiki/File_talk:Colorado_counties_until_November_15,_2001.svg" title="File talk:Colorado counties until November 15, 2001.svg">the talk page</a> for more details.