Frisco (WBAP/KLIF) – The City of Frisco is growing so quickly the United States Postal Service is adding a fourth zip code. Starting July 1st, about 10,000 residential and business addresses who currently use the 75034 zip code will use the new 75036 zip code. The change will affect the area bordered by Cottonwood Brand and Main Street on the north, Teel Parkway on the east, Boyd Road/Lebanon Roads/Lewisville Lake on the south and Lewisville Lake on the west. No changes are being made to those in the 75033 and 75035 zip codes. The post office says it will continue to deliver mail with the old zip code for a period of one year to allow customers to make the transition to the new zip code.