As of 2010, the municipality had a total population of 20,349,[1] up from 16,538 as of 2005.[2] It covers an area of 171.04 km2.
As of 2010, the town of Larráinzar (San Andrés Larráinzar) had a population of 2,364.[1] Other than the town of Larráinzar, the municipality had 77 localities, none of which had a population over 1,000.[1]