Built by Islam Shah Suri, also known as Salim Shah, son and successor of Sher Shah Suri in 1546, Salimgarh Fort was constructed on an island of river Yamuna. However, only the walls were completed when Salim Shah died and the construction was abandoned. Later several Mughal rulers camped here before the creation of Shahjahanabad, which includes Humayun who stayed here for three days before recapturing Delhi in 1555. In 1622 AD, Jahangir constructed a bridge and connected it to the mainland, which was later removed by the British when they built the railway line through it. Shah Jahan, the next emperor connected this fort with Red Fort and the fort finally became a state prison during the reign of Aurangzeb. The British continued using it as a prison and kept its artillery units here after the war of 1857. The leaders of Indian National Army were imprisoned here in 1945. The fort has now been renamed as Swatantrata Senani Smarak (Freedom Fighters’ Memorial) as a memorial has been developed for the freedom fighters in side the fort. The barracks where soldiers were kept as prisoners have been converted into their memorials. The memorial houses INA uniforms, personal belongings and some photographs.
The fort is somewhat polygonal in shape and is enclosed by solid rubble masonry walls. The entry to the fort is from its northern gate also called Bahadur Shahi Gate as Bahadur Shah Zafar constructed it in 1854-55 AD. The gate is built of brick masonry with red sandstone sparingly used. The fort contained several lofty bastions but fortunately or unfortunately the ruins of those can be only be seen today.