Coconino County is a county located in the north central part of the U.S. state of Arizona. The population was 134,421 at the 2010 census. The county seat is Flagstaff. The county takes its name from Cohonino, a name applied to the Havasupai. It is the second largest county by land area in the 48 contiguous United States, behind San Bernardino County, California, with its making it larger than each of the nine smallest states.