The San Lorenzo Department includes important ports on the Paraná River, such as the city of San Lorenzo itself and Puerto General San Martín (which ships 50% of the Argentine exports of soybean). This area also forms part of the so-called Industrial Corridor that stretches south towards Rosario and reaches up to San Nicolás de los Arroyos.
References
Inforama - Municipalities of the San Lorenzo Department.
"San Lorenzo Department" (in Spanish). Municipal Affairs Federal Institute (IFAM), Municipal Affairs Secretariat, Ministry of Interior, Argentina.