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.

Excavations began in 1900 by Friedrich Delitzsch, and were continued in 1903–1913 by a team from the Deutsche Orient-Gesellschaft led initially by Robert Koldewey and later by Walter Andrae.

According to the Oxford Companion to the Bible, Assur was "built on a sandstone cliff on the west bank of the Tigris about 35 km (24 mi) north of its confluence with the lower Zab River".

The historically unverified king Ushpia is credited with dedicating the first temple of the god Ashur in his home city, although this comes from a later inscription from Shalmaneser I in the 13th century.

[13] In around 2000 BC, Puzur-Ashur I founded a new dynasty, with his successors such as Ilushuma, Erishum I and Sargon I leaving inscriptions regarding the building of temples to Ashur, Adad and Ishtar in the city.

As the region enjoyed relative peace and stability, trade between Mesopotamia and Anatolia increased, and the city of Ashur greatly benefited from its strategic location.

The city was subsequently subjugated by the king of Mitanni, Shaushtatar in the late 15th century, taking the gold and silver doors of the temple to his capital, Washukanni, as spoils.

The Assyrians reaped the benefits of this triumph by taking control of the eastern portion of the Mitanni Empire, and later also annexing Hittite, Babylonian, Amorite and Hurrian territory.

Ashur-nasir-pal II (884–859 BC) moved the capital from Assur to Kalhu (Calah/Nimrud) following a series of successful campaigns and produced some of the greatest artworks in the form of colossal lamassu statues and low-relief depictions of the royal court as well as battles.

[15] He died in battle and his son and successor Sennacherib (705–682 BC) abandoned the city, choosing to magnify Nineveh as his royal capital.

The Assyrians of Mada (Media) and Athura (Assyria) had been responsible for gold and glazing works of the palace and for providing Lebanese cedar timber, respectively.

[19] The city revived during the Parthian Empire period, particularly between 150 BC and 270 AD, its population expanding and it becoming an administrative centre of Parthian-ruled Assuristan.

German semiticist Klaus Beyer (1929-2014) published over 600 inscriptions from Mesopotamian towns and cities including Ashur, Dura-Europos, Hatra, Gaddala, Tikrit and Tur Abdin.

Assur was captured and sacked by Ardashir I of the Sasanian Empire c. 240 AD, whereafter the city was largely destroyed and much of its population was dispersed.

[26] An AP report from December 2016 after the Iraqi forces had retaken the area, said that the militants tried to destroy the city's grand entrance arches, but they remained standing and a local historian described the damage as "minor".