 It limits with the populous Rosario Department and the Paraná River in the east; and from there (going clockwise) with the departments of Constitución (south), Caseros (east), Iriondo (east and north) and San Jerónimo (north).The department has an area of 1,867 km² and a population of over 140,000 inhabitants.Its head town and most populated urban center is San Lorenzo (population 43,000).