In history, "citadel" refers to a fortified area within a city or settlement, typically elevated and designed for defense purposes. In the context of the Harappan Civilization, also known as the Indus Valley Civilization, the citadel was a prominent feature of their urban planning.

During the Harappan Civilization, which flourished around 2600 to 1900 BCE in the area of modern-day Pakistan and northwest India, cities were laid out on a grid pattern with well-planned streets and drainage systems. Each city typically had two main sections: the lower town and the citadel.

The citadel was situated on a raised platform and often surrounded by thick walls, providing protection from external threats. It was likely the administrative and religious center of the city, housing important buildings such as the ruling authority's residence, administrative offices, and possibly temples or other religious structures.

Archaeological excavations at sites such as Mohenjo-Daro and Harappa have revealed the remains of citadels, offering insights into the urban organization and social structure of the Harappan Civilization. These citadels played a crucial role in shaping the identity and function of Harappan cities during their heyday.