Aššur, also known as Ashur and Qal'at Sherqat, was the capital of the Old Assyrian Empire, the Middle Assyrian Empire, and for a time, of the Neo-Assyrian Empire. The remains of the city lie on the western bank of the Tigris River, north of the confluence with its tributary, the Little Zab, in what is now Iraq, more precisely in the al-Shirqat District of the Saladin Governorate.
Occupation of the city itself continued for approximately 4,000 years, from c. 2600 BC to the mid-14th century AD, when the forces of Timur massacred its population. The site is a World Heritage Site, having been added to that organisation's list of sites in danger in 2003 following the conflict that erupted following the US-led 2003 invasion of Iraq and as a result of a proposed dam which would flood some of the site. Assur lies 65 kilometres south of the site of Nimrud and 100 km south of Nineveh.