The neighboring municipalities of Alajärvi are Alavus, Kuortane, Kyyjärvi, Lappajärvi, Lapua, Perho, Soini, Vimpeli and Ähtäri.

[10] The chart below, describing the development of the total population of Alajärvi from 1975 to 2020, encompasses the municipality's area as of 2021.

[12] There are several buildings in the town and surrounding area designed by architect Alvar Aalto, both from the very early and later stages of his career: the Youth Association building (1919), Myllykangas farmhouse alterations (1920), Villa Väinölä (1926), Villa Flora (Aino Aalto, 1926), Municipal Hospital (1928), Grave memorials in the Church of Gabriel cemetery (1918, 1940, 1944), and the Administrative Centre (1965-1970) and Library (design 1966, built 1991).

[15] The men's pesäpallo club Alajärven Ankkurit competes in the Superpesis national league, playing at Kitro Stadium.

Also, Alvar Aalto spent summers in Alajärvi in his youth and even lived there until his marriage in 1925.