Where is 303 area code? 

303 – Denver, CO

What area code is 303

Denver, Colorado is located on the plateaus east of the Rocky Mountains approximately 540 km north of Albuquerque, New Mexico and 157 km south of Cheyenne, Wyoming.

Denver is often called the Mile-High City, because it is located exactly 1609 meters above sea level. The Rocky Mountains get a lot of snow every Winter, but the climate in Denver is mild. The city has on average 300 days of annual sunshine and when winter storms, the snow melts fairly quickly.