The Eilenriede (literally 'alder marsh' in German, meaning 'marsh populated with alder trees') is a 640-hectare (1,600-acre) municipal forest in Hanover, Germany. It is the largest urban city forest in Germany, one of the largest in Europe, and is nearly twice the size of Central Park in New York. The biggest German urban park in the strict sense of the word, however, is the 375-hectare (930-acre) English Garden in Munich.

In Germany, the Eilenriede is part of a group of inner-city and near-city forest areas, like the Rostock Heath (6,000 hectares or 15,000 acres), the Dresden Heath (5,900 hectares or 15,000 acres), the Frankfurter Stadtwald (4,800 hectares or 12,000 acres) and the Berliner Grunewald (3,000 hectares or 7,400 acres). The Eilenriede is around the same size as the Stadtwald in Duisburg (600 hectares or 1,500 acres) and is nearly twice as large as Central Park (340 hectares or 840 acres) in New York.

Eilenriede encloses the south of the city roughly in the shape of a mirror-inverted letter 'C', extending about 6 kilometres (3.7 mi) from north to south. Reaching in its southwest to the Masch Lake, the Eilenriede is traversed by a network of 80 kilometres (50 mi) of walking, 38 kilometres (24 mi) of bicycle, and 11 kilometres (6.8 mi) of riding paths.

The city forest offers a range of different possibilities in leisure activities, like: