Your request for suggested places to visit within 300 miles of Mesa, Arizona surprisingly did not elicit the most visited site in the state-the Grand Canyon. Additionally I would suggest Monument Valley, an icon of the American Southwest, and one of my favorite Arizona destinations Canyon de Chelly. Finally, if you decide to head in the direction of Tucson consider visiting Kartchner Caverns one of the largest cave complexes in the United States.

Happy travels, John