Kolagiri fortress, also the Queen's fortress, is a stronghold of the feudal era (end of the 18th century) in eastern Georgia, in the village of Kolagiri in present-day Bolnisi municipality. It stands on the left side of the Algeti River, on open ground equally approachable from every side. Of the fortresses of this type built in Kartl-Kakheti, Kolagiri is one of the last. It was built in 1788–1798 by Queen Darejan. In 1801 Darejan herself wrote: "I built the great fortress and wall of Kolagiri." The pre-drawn plan from which the fortress was built has survived. The fortress is square in plan and covers 2,000 m². It is built of selected unworked stone, with brick used for the machicolations and the decorative treatment of the entrance towers. The 6-m wall is thicker below and thinner above. A so-called "battle path" runs around the whole fortress at the level of the towers' second story.