Kentucky is located in the central and eastern part of the United States, with a land area of 104,749 square kilometers and a population of 4.04 million. The capital city is Frankfurt, which has the same name as the German city. Kentucky has a lot of foreign investment and exports more goods to China. The state has many mineral resources, mainly coal, oil wells, natural gas, and other industrial building materials. Due to the lush vegetation, forest resources are also abundant. The state's main transportation relies on air freight, and the main airport is Louisville International Airport (LOU), which is also the transshipment center for UPS express, and it is quite convenient to send international express here. The abbreviated ZIP code for Kentucky is KY and the area code is 270 – 502 – 606 – 859. The zip codes for the major cities are as follows: Louisville is 40201-40299. The zip code for Lexington is 40502-40598.