Standing over the Cinturón del Pardo (the El Pardo ringroad), the Puerta de Hierro gate was built during the reign of Ferdinand VI in 1751. It is the work of architect Francisco Nagle. He was assisted by Francisco Moradillo and sculptor Olivieri, both responsible for the decorative elements.

 The monument is of a classic baroque structure, following the Italian and French styles, with a semi-circular arch flanked by two pillars to which it is linked by original wrought-iron railings. A pediment with the royal coat of arms can be seen at the top.

 Standing in the Monte del Pardo area, the Puerta de Hierro gate was the entry point for a restricted area where Ferdinand VI used to hunt. The area was sealed off by a wall made of stone, brick and wire fencing, the remains of which can still be seen. The area contains various properties belonging to the royal family and villages that have expanded with the years, including El Pardo and Mingorrubio.

 Unlike other gates in Madrid, this one is outside the city, close to the mansion known as Quinta de Goya, where the painter had his studio. It stands at a point where various main roads meet and recently, when the road to Coruña was widened, it had to be dismantled piece by piece and re-assembled a few metres away from its original location.