Iowa is located in the Midwest region of the United States, with a land area of 145,743 square kilometers and a population of 3.09 million. The state's manufacturing industry is very developed and ranks among the top in the United States. In addition, the state's population is highly educated, with more than 90 percent of the population having a college education, and the state is well-policed. Agriculture is also extremely developed in Iowa, second only to California. The state's capital, Des Moines, is located at the confluence of two rivers, serving as the local transportation hub and financial center. Iowa's rail and road systems are relatively developed, and inland shipping is also relatively developed due to the Mississippi River. The ZIP code for Iowa is 50322, and the area codes for the state are: 319, 515, 563, 641, 712.