How long should a letter take to go from Denver CO Oklahoma City OK?

First-Class Mail® service generally takes between 1 to 3 business days to be delivered. The distance between Denver, CO and Oklahoma City, OK is approximately 500 miles. For First-Class Mail®, the transit time is typically 2-3 business days. Adding the time for processing and transportation, it can take up to 5 business days for a letter to go from Denver, CO to Oklahoma City, OK.