This is the National Destination Code(NDC):801 page list. Its detail is as below.
Area code 801 is one of the original 86 area codes created by AT&T and the Bell System in 1947. It originally served the entire state of Utah. In 1997, area code 801 was split, and some of the phone numbers had to be updated to area code 435 on that date. In 2009, area code 385 was created as an overlay to area code 801. Currently, the largest city it serves is Salt Lake City, UT, and it overlaps coverage areas with area code 385.