Syr Darya in the context of "Erigyius"

Cyrus II of Persia (c. 600 – 530 BC), commonly known as Cyrus the Great, was the founder of the Achaemenid Empire. Hailing from Persis, he brought the Achaemenid dynasty to power by defeating the Median Empire and embracing all of the previous civilized states of the ancient Near East, expanding vastly across most of West Asia and much of Central Asia to create what would soon become the largest empire in history at the time. The Achaemenid Empire's greatest territorial extent was achieved under Darius the Great, whose rule stretched from Southeast Europe in the west to the Indus Valley in the east.

After absorbing the Median Empire, Cyrus conquered Lydia and eventually the Neo-Babylonian Empire, granting him control of Anatolia and the Fertile Crescent, respectively. He also led a major expedition into Central Asia, where his army brought "into subjection every nation without exception" before he allegedly died in battle with the Massagetae, a nomadic Eastern Iranian people, along the Syr Darya in December 530 BC. However, according to Xenophon of Athens, Cyrus did not die fighting and had instead returned to the capital city of Pasargadae. Regardless of the date of his death, he was succeeded by his son Cambyses II, whose campaigns into North Africa led to the conquests of Egypt, Nubia, and Cyrenaica during his short rule.

Transoxiana or Transoxania (lit. 'Land beyond the Oxus', now called the Amu Darya) is the Latin name for the region and civilization located in lower Central Asia roughly corresponding to eastern Uzbekistan, western Tajikistan, parts of southern Kazakhstan, parts of Turkmenistan and southern Kyrgyzstan. The name was first coined by Alexander the Great in the 4th century BC when Alexander's troops conquered the region. The region may have had a similar Greek name in the days of Alexander the Great, but the earlier name is no longer known. Geographically, it is the region between the rivers Amu Darya to its south and the Syr Darya to its north.

The region of Transoxiana was one of the satrapies (provinces) of the Achaemenid Empire of Persia under the name Sogdia. It was defined within the classical world of Persia to distinguish it from Iran proper, especially its northeastern province of Khorasan, a term originating with the Sasanians, although early Arab historians and geographers tended to subsume the region within the loosely defined term "Khorasan" designating a much larger territory. The territories of Khwarazm, Sogdiana, Chaghaniyan, and Khuttal were located in the southern part of Transoxiana; Chach, Osrushana, and Farghana were located in the northern part.

Sogdia (/ˈsɒɡdiə/) or Sogdiana was an ancient Iranian civilization between the Amu Darya and the Syr Darya rivers, and in present-day Uzbekistan, Turkmenistan, Tajikistan, Kazakhstan, and Kyrgyzstan. Sogdiana was also a province of the Achaemenid Empire, and listed on the Behistun Inscription of Darius the Great. Sogdiana was first conquered by Cyrus the Great, the founder of the Achaemenid Empire, and then was annexed by the Macedonian ruler Alexander the Great in 328 BC. It would continue to change hands under the Seleucid Empire, the Greco-Bactrian Kingdom, the Kushan Empire, the Sasanian Empire, the Hephthalite Empire, the Western Turkic Khaganate, and the Muslim conquest of Transoxiana.

The Sogdian city-states, although never politically united, were centered on the city of Samarkand. Sogdian, an Eastern Iranian language, is no longer spoken. However, a descendant of one of its dialects, Yaghnobi, is still spoken by the Yaghnobis of Tajikistan. It was widely spoken in Central Asia as a lingua franca and served as one of the First Turkic Khaganate's court languages for writing documents.

The Oghuz Yabgu State or Oghuz il (Old Turkic: Oghuz Land) was a Turkic state, founded by Oghuz Turks in 750, located geographically in an area between the coasts of the Caspian and Aral Seas. Oghuz tribes occupied a vast territory in Kazakhstan along the Irgiz, Yaik, Emba, and Uil rivers, the Aral Sea area, the Syr Darya valley, the foothills of the Karatau Mountains in Tien-Shan, and the Chui River valley (see map). The Oghuz political association developed in the 9th and 10th centuries in the basin of the middle and lower course of the Syr Darya and adjoining the modern western Kazakhstan steppes.

The Kipchaks, also spelled Qipchaqs, known as Polovtsians (Polovtsy) in Russian sources, were Turkic nomads and then a confederation that existed in the Middle Ages inhabiting parts of the Eurasian Steppe.

First mentioned in the eighth century as part of the Second Turkic Khaganate, they most likely inhabited the Altai region from where they expanded over the following centuries, first as part of the Kimek–Kipchak confederation and later as part of a confederation with the Cumans. There were groups of Kipchaks in the Pontic–Caspian steppe, China, Syr Darya, and Siberia. Cumania was conquered by the Mongol Empire in the early 13th century.

The Baikonur Cosmodrome is a spaceport operated by Russia within Kazakhstan. Located in the Kazakh city of Baikonur, it is the largest operational space launch facility in terms of area. All Russian crewed spaceflights are launched from Baikonur.

Situated in the Kazakh Steppe, some 90 metres (300 ft) above sea level, it is 200 kilometres (120 mi) to the east of the Aral Sea and north of the Syr Darya. It is close to Töretam, a station on the Trans-Aral Railway. Russia, as the official successor state to the Soviet Union, has retained control over the facility since 1991; it originally assumed this role through the post-Soviet Commonwealth of Independent States (CIS), but ratified an agreement with Kazakhstan in 2005 that allowed it to lease the spaceport until 2050. It is jointly managed by Roscosmos and the Russian Aerospace Forces.

The Kyzylkum Desert (Uzbek: Qizilqum; Kazakh: Qyzylqūm) is the 15th largest desert in the world. Its name means 'Red Sand' in Turkic languages. It is located in Central Asia, in the land between the confluent rivers Amu Darya and Syr Darya, a region historically known as Transoxania. Today it is divided among Kazakhstan, Turkmenistan and Uzbekistan. It covers about 298,000 km (115,000 sq mi).