In 1804 city wall and ramparts were stripped down and re-naturalized to parks, but the spatial division between the two lakes was retained.

The Alster River enters the Außenalster in the North at Krugkoppelbrücke and leaves it in the South at Kennedybrücke.

Alsterufer and Harvestehuder Weg on the western shore include a number of consular missions, like the U.S. Consulate General.

Usually during May, the Japanese community in Hamburg organizes the annual Kirschblütenfest (Cherry Blossom Festival) around Außenalster.

Less regularly − that is, only when a winter becomes cold enough and the Außenalster's ice strong enough − the Alstereisvergnügen is held on the frozen Alster.

Formerly private gardens on the western side were made public while Hamburg was host to the Internationale Gartenbauausstellung (International Horticulture Show, IGA) in 1953.