According to the 2010 Census St Mary's,KS has a population of 2,627.
Of those 2,627 1,260 are male and 1,367 female.
Now to the good part. the under 18 population is 1,012 which is 38 percent of the town's population.
Children under 18 are a substantial minority in St Mary's I believe that the SSPX presence there is causing this.
the age 35-49 is the largest age group with 396.
18 and over is 1,615
there are 236 hispanics in that town and 2,393 whites.