Mexican Hat is a census-designated place (CDP) in Utah in the United States. It is on the San Juan River on the northern edge of the Navajo Nation's borders in south-central San Juan County. The population was 31 in the 2010 census, a sharp decline from the previous two censuses.

The San Juan River is a major tributary of the Colorado River in the Southwestern United States, providing the chief drainage for the Four Corners region of Colorado, New Mexico, Utah, and Arizona. Originating as snowmelt in the San Juan Mountains of Colorado, it flows 383 miles (616 km) through the deserts of northern New Mexico and southeastern Utah to join the Colorado River at Glen Canyon.