The Colorado State Library has archived the 1981, 1991, and 2001 reports of the former Colorado Reapportionment Commission.  The Colorado Reapportionment Commission was created in 1974 and operated through the 2011 redistricting cycle, drawing the state senate and state house districts.  The reports include the final approved state legislative maps from each cycle.

1981 Report of the Colorado Reapportionment Commission
1991 Report of the Colorado Reapportionment Commission
2001 Report of the Colorado Reapportionment Commission