All recorded cultural resources receive a Smithsonian number. This is a trinomial number with a state numerical designation (Colorado is #5), a two letter designation for the county, and a sequential number for the resource. For example, the first recorded site in Rio Blanco county is 5RB1. Site numbers are assigned by writing the OAHP office or calling 303-866-5216. Do not assign a new site number to previously recorded sites with existing site numbers. Please contact the OAHP staff to determine the correct site number if a structure has been moved or if new construction connects two previously separate properties.