Parque Natural Municipal Ribera Norte, Nature reserve in San Isidro, Argentina.

Parque Natural Municipal Ribera Norte covers 50 hectares of tidal wetland on the Río de la Plata in Acassuso, San Isidro, crossed by a 1,200-metre trail. Its natural formation, unlike other urban reserves built on rubble fill, follows the delta model: shallow basins flooded almost daily, raised albardones edges where riverside woodland grows, and reed belts over sandy beaches. A native plant nursery stands within the reserve.

The area was first protected in 1982, making it the oldest municipal reserve in Argentina. Its legal status as a perpetual protected space and its formal inauguration came in 1988, under municipal ordinance No. 6541 during the tenure of San Isidro mayor Melchor Posse. The reserve covers 50 hectares of coastal wetland on the Río de la Plata.

The park's logo shows the red flowers of the ceibo, Argentina's national flower, beside a drawing of the white-throated hummingbird, a local species rarer than the green hummingbird. The nursery grows native riverside plants for reintroduction into the reserve and for street trees in San Isidro. Guided walks, some at night, are led by specialist guides and often host school groups.

Access is from Camino de la Ribera (formerly El Fomentista street), between Vicente López and Planes and Almafuerte streets, at Avenida del Libertador 15400. Besides car or taxi, several bus lines serve the area, and the Las Barrancas coastal station on the Tren de la Costa is nearby. Guided walks with specialized guides are offered, both daytime and nighttime, and school groups visit frequently.

The reserve protects one of the last wild stretches of the Río de la Plata coast within the city. This remaining natural corridor shows what the riverside looked like before urban development.