Mesa is located in Maricopa County and is the most populous city in the East Valley, with 504 258 people. After Phoenix and Tucson, this is the third-largest city in the state, with a total area of 361,09 square kilometers. The first school in the city was built in 1879, and today more than 40 000 students are currently enrolled in Mesa’s colleges and universities. The 1950s and 1960s were the golden decades of industry and agriculture. Many companies, especially early aerospace companies, grew up at this time. Sloan Park, an American baseball park located in Mesa, is a training home for the Chicago Cubs.