structural:reformatting, structural:summarization, information:filtering
Geography

The desert covers roughly seventy percent of Turkmenistan, a long east–west swath. It sits east of the Caspian Sea which has a steep east bank. It adjoins, to the north, the long delta feeding the South Aral Sea further north, another endorheic lake, about 58 m (190 ft) higher than the Caspian Sea. The delta is that of the Amu Darya river to the northeast, demarcating the long border with the Kyzylkum Desert of Uzbekistan. The desert is divided into three regions, the elevated northern Trans-Unguz Karakum, the low-lying Central Karakum, and the southeastern Karakum, home to a chain of salt marshes. Since the early 1980s, the relatively small desert extension, the Aralkum, has come to occupy most of the former seabed of the Aral Sea, about 15,440 sq mi (40,000 km). The sea has fluctuated over millennia, but its majority loss during the Soviet Union 's existence coincided with great irrigation projects. The North Aral Sea was partly restored, but the South Aral Sea ebbed to a small-size stasis at its river mouth, which itself dried up by 2014, leaving only fragments of the former sea behind, such as Barsakelmes Lake.

Within the north-west edge of the desert used to be a river. In the late Pleistocene, the Amu Darya used to flow beyond the Aral Basin to Sarykamysh Lake then to the Caspian Sea. Sedimentation and floods during a pluvial period led to overflow to the Zeravshan River valley to the east. The two flows merged and formed or expanded Horezm Lake, which had been formed by the earlier Khvalinian period, and as it overflowed northwards it carved its link with the Aral Sea along the Akcha Dar'ya population corridor of that low, gentle valley (a remote community of Western Uzbekistan and north-east Turkmenistan).