La Unión is a city located in the state of Guerrero in Mexico, serving as the municipal seat of La Unión de Isidoro Montes de Oca. The city is situated within this municipality, which shares its administrative center with the city of the same name.
According to census data from 2005, La Unión had a population of 3,079 residents, reflecting its status as a modest-sized municipal center in the Guerrero region.