This is one of two Crow Reservation CDP's or census designated places. According to the 2010 census, the population of St. Xavier is 83. There are a total of 36 housing units in the cdp which gives the cdp an average household size of about 2.2 persons per housing unit. Native Americans account for 46 of the population of 83 or 57% of the cdp's population. Whites account for 32 of the population or 40% of the population. Mixed bloods account for 1% of the population, while Mexicans account for 0.5% of the population of St. Xavier, Montana. The cdp covers an area of 5.6 sq. mi. Elevation is 3,077 feet above sea level. The zip code is 59075. Economically, the cdp is not doing so well. Around 40% of the cdp's citizens live below the poverty line. Below are several google earth photos of St. Xavier.