Alte Post, Cultural heritage monument in Neustadt, Hamburg

Alte Post is a listed building on Poststraße in Hamburg's Neustadt, completed in 1847 to designs by Alexis de Chateauneuf. Its facade combines unplastered brick with Gothic-style sandstone elements in a round-arch style inspired by Italian Renaissance palazzi. A 40-metre clock tower, modelled on the Belfry of Bruges, rises above the main entrance.

Built from 1845 to 1847 to designs by Alexis de Chateauneuf, the Alte Post opened on 2 January 1848 as the Hamburgische Stadtpost, housing also the Thurn und Taxis, Hanoverian and Swedish post offices. In 1868 it became the seat of the North German Federal Post Office, and from 1887 the city used it for administration and archives. The HWWA moved in in 1924, the year the building was listed; after the 1962 storm flood damaged its magazine rooms, the building was gutted and rebuilt in 1968–1971.

The building's name refers to its role as Hamburg's main post office, opened on 2 January 1848. The portals of the separate entrances still carry the coats of arms of the Hamburg city post, Thurn und Taxis, Hanover and Sweden, showing how several postal services shared the house. Today the ground floor holds shops and the upper floors are rented as offices.

The building sits in the Neustadt area and is easy to reach on foot from the nearby streets and public transport stops. The exterior can be seen at any time of day, but access to the interior depends on what the building is currently being used for.

The clock tower was modelled on the Belfry of Bruges and reaches 40 metres; an optical telegraph (semaphore) once stood on top, linking Hamburg with Cuxhaven at the mouth of the Elbe. It opened on 23 July 1848 but was shut down the following year after an electric Morse telegraph took over the Cuxhaven line on 15 October 1848.