San Nicolás is one of the 135 parties of the Argentine province of Buenos Aires, located in the interior of this province. Its capital city is San Nicolás de los Arroyos. It is the northernmost party in the province. It is located in the northeast end of the province of Buenos Aires, on the Paraná River and within the Rosario - La Plata industrial corridor. It is bordered to the west by Pergamino's party, to the south by Ramallo, to the east by the Paraná river, which separates it from the Province of Entre Ríos, and to the north by Arroyo del Medio, the natural boundary with the Province of Santa Fe.
Road accesses are km 224 of national route 9 in a north-south direction. Route 188 in an east-west direction connects it with the corridor of the Pacific Ocean Route 9. On the side of the highway is "El Parador" of buses. On the other hand, it is crossed by the General Miter railway, operated by the company Nuevo Central Argentino, in a north-south direction. The city has a bus terminal. And loading-unloading with railroad tracks at the foot of cranes of the Paraná waterway, with an important port at km 243, which serves the industrial and cereal industry. A modern, concessioned highway, from 1978, arrives in Buenos Aires from Rosario. In San Nicolás, the national route 188 to San Rafael is born.
It serves as a connection to the city of Junín, where the road junction with National Route 7 is located, the main international communication route between Buenos Aires, passing through San Luis and Mendoza, and being one of the main routes of Mercosur. Route 188 goes directly to the Puerto Nuevo de San Nicolás, suitable for large vessels. From it, cereals, irons, steels and different raw materials go out to different parts of the world.