St. Xavier or Saint Xavior[2] is an unincorporated community and census-designated place (CDP) in Big Horn County, Montana, United States.

[4] It is located on the Crow Indian Reservation[5] along the Bighorn River.

As of the census[7] of 2000, there were 67 people, 20 households, and 18 families residing in the CDP.

10.0% of all households were made up of individuals, and none had someone living alone who was 65 years of age or older.

There were 25.0% of families and 40.7% of the population living below the poverty line, including 70.4% of under eighteens and none of those over 64.