The Secret Tower, a round tower of the Nizhny Novgorod Kremlin, is located in the elevated part between the Korymislova and Northern Towers. It is distinguished from other round towers by the presence of a watchtower on the tent roof, similar to the Clock and Nikolskaya Towers.

The tower got its name due to a secret passage to the river Pochaïna, which was dug under the fortress walls. In case of a prolonged siege of the Nizhny Novgorod Kremlin, one could exit to the river through this underground passage and stock up on water. In the 19th century, during earthworks for the arrangement of the Zeleny Congress, this hiding place was filled in, and to drain water, the underground stream was enclosed in a collector made of wooden pipes. According to legend, near the Kremlin hill, at the source of Pochaïna, lies a stone block, and if it shifts, the stream will break free and wash away the city. The tower also harbored destructive power, as gunpowder was stored within its walls, and nearby, in a ravine, a gunpowder factory, Zeleiny Dvor, was built. The tower received its second name from the factory, on Zeleny. The third name, Mironositskaya, is related to its proximity to the church of the Holy Myrrhbearers. Like other round towers of the Nizhny Novgorod Kremlin, the Secret Tower has three tiers with loopholes and one tier with battlements.

In the 17th century, a copper cannon was installed on the Secret Tower, and between 1785 and 1790, it was converted into a food warehouse by order of the Nizhny Novgorod governor I.M. Rebinder. From 1826 to 1887, the tower housed a battalion arsenal for storing military equipment and weapons. Later, it was given over to the archive of the Nizhny Novgorod voivode. During the Great Patriotic War, anti-aircraft guns were installed in place of the demolished tent to protect the city from air raids by the German army. During the restoration in the 1960s, the tent roof was restored.

In 2019, after the roof repair, installation of ceilings and barriers, the observation deck of the upper tier of the tower was opened for the first time, where even the staff of the museum-reserve were previously not allowed.