Grand County is a county on the east central edge of the U.S. state of Utah, United States. As of the 2020 United States census, the population was 9,669. Its county seat and largest city is Moab. Grand County is home to one of the nine statewide regional campuses of Utah State University and serves as a gateway to both Arches and Canyonlands National …Grand County is a county on the east central edge of the U.S. state of Utah, United States. As of the 2020 United States census, the population was 9,669. Its county seat and largest city is Moab. Grand County is home to one of the nine statewide regional campuses of Utah State University and serves as a gateway to both Arches and Canyonlands National Parks.