Necochea is a port city in the southwest of the province of Buenos Aires, Argentina, located on the Atlantic coast, on the edge of the Quequén Grande river, 528 km (328 mi) from Buenos Aires City and 120 km (75 mi) southwest from Mar del Plata. It has 89,000 inhabitants as per the 2001 census and it is the seat of government for Necochea Partido, a partido of Buenos Aires Province. On the mouth of the Quequen river, the port of Quequen, one of the most important ports in Argentina, is the gateway for the agricultural production of the southeast of the Province of Buenos Aires.
The majority of inhabitants of Necochea are Argentines, but throughout the years a large number of Danes have settled there. There are smaller "pueblos" or communities in Necochea mainly founded by Danes and other Nordic settlers.