Larsa (the Biblical Ellasar, Genesis 14:1), was an important city of ancient Babylonia, the site of the worship of the sun-god, Shamash, represented by the ancient ruin mound of Senkereh (Senkera ). It lay 15 miles southeast of the ruin mounds of Erech, near the east bank of the Shatt-en-Nil canal.

Larsa is mentioned in Babylonian inscriptions as early as the time of Ur-Gur , 2700 or 2800 BC, who built or restored the ziggurat (stage-tower) of E-Babbar, the temple of Shamash. Politically it came into special prominence at the time of the Elamite conquest, when it was made the centre of Elamite dominion in Babylonia, perhaps as a special check upon the neighbouring Erech, which had played a prominent part in the resistance to the Elamites. At the time of Hammurabi successful struggle with the Elamite conquerors it was ruled by an Elamite king named Eriaku, the Arioch of the Bible, called Rim-Sin by his Semitic subjects. It finally lost its independence under Samsu-Iluna, son of Hammurabi, and from that time until the close of the Babylonian period it was a subject city of Babylon.

Loftus conducted excavations at this site in 1854. He describes the ruins as consisting of a low, circular platform, about 4.5 miles in circumference, rising gradually from the level of the plain to a central mound 70 ft. high. This represents the ancient ziggurat of the temple of Shamash, which was in part explored by Loftus. From the inscriptions found there it appears that, besides the kings already mentioned, Hammurabi, Burna-buriash (buryas) and the Nebuchadnezzar II of Babylon restored or rebuilt the temple of Shamash. The excavations at Senkereh were peculiarly successful in the discovery of inscribed remains, consisting of clay tablets, chiefly contracts, but including also an important mathematical tablet and a number of tablets of a description almost peculiar to Senkereh, exhibiting in basrelief scenes of everyday life. Loftus found also the remains of an ancient Babylonian cemetery. From the ruins it would appear that Senkereh ceased to be inhabited at or soon after the Persian conquest.