Alamín Tower is a remnant of the Postigo Gate in the old city wall of Guadalajara, Spain. Over the Alamn valley and to the rear of the Santa Mara co-cathedral, on the former northern wall side, is where you'll find this structure. It once served as a watchtower above the entrance from the Alamn area and is now a visitor centre for the city wall.

The tower and the Infantas bridge together constitute a larger complex. From its foundation at the foot of the ravine, the tower rises to a height of around 20 metres. The walls are nearly two metres in height and they are constructed of mortar and masonry. The two levels are linked by a tight spiral stairwell. It is reached via a plain lintelled entrance on the south side, at ground level, from the street. On the upper level, on the same side, is the tower's original entrance: a semicircular arched doorway. Upstairs, on the north side of the tower (which faces El Alamn), are two smaller balconies. Some doorways within the walls really lead outdoors.

As part of the wall system that was improved and fortified between the 13th and 14th centuries, the Alamn keep was constructed. Getting there required crossing the Infantas Bridge, which led to the city's primary Muslim suburb of El Alamn, which was located in the city's northeast. After it stopped being needed for military purposes in the 18th century, it became a medical centre. After being closed off for many years, the Guadalajara Walls Interpretation Center reopened to the public in 2004.