Kansas is an inland state in the central part of the United States. From the map, the shape of the state is similar to a rectangle, and the terrain is mainly plain. The state capital is Topeka. Kansas has a land area of 210,000 square kilometers and a population of nearly 3 million. The economy of Kansas is mainly based on agriculture and manufacturing, especially the wheat production ranks first in the United States. Wichita is the state's largest city and a manufacturing hub. Second, Kansas City is also an important city, with an important airport in the state: Kansas City International Airport. The abbreviated ZIP code for Kansas is KS, the area code is 316 - 620 - 785 - 913, and the ZIP codes for major cities are as follows: Topeka 66601-66699; Wichita 67201-67278; Kansas The zip code of Kansas City is 66101-66160.