Sistan Basin in the context of "Helmand River"

Afghanistan, officially the Islamic Emirate of Afghanistan, is a landlocked country located at the crossroads of Central and South Asia. It is bordered by Pakistan to the east and south, Iran to the west, Turkmenistan to the northwest, Uzbekistan to the north, Tajikistan to the northeast, and China to the northeast and east. Occupying 652,864 square kilometers (252,072 sq mi) of land, the country is predominantly mountainous with plains in the north and the southwest, which are separated by the Hindu Kush mountain range. Kabul is the country's capital and largest city. Afghanistan's population is estimated to be between 40 and 50 million.

Human habitation in Afghanistan dates to the Middle Paleolithic era. Popularly referred to as the graveyard of empires, the land has witnessed numerous military campaigns, including those by the Persians, Alexander the Great, the Maurya Empire, Arab Muslims, the Mongols, the British, the Soviet Union, and a US-led coalition. Afghanistan also served as the source from which the Greco-Bactrians and the Mughals, among others, rose to form major empires. Because of the various conquests and periods in both the Iranian and Indian cultural spheres, the area was a center for Zoroastrianism, Buddhism, Hinduism, and later Islam. The modern state of Afghanistan began with the Durrani Afghan Empire in the 18th century, although Dost Mohammad Khan is sometimes considered to be the founder of the first modern Afghan state. Afghanistan became a buffer state in the Great Game between the British Empire and the Russian Empire. From India, the British attempted to subjugate Afghanistan but were repelled in the First Anglo-Afghan War; the Second Anglo-Afghan War saw a British victory. Following the Third Anglo-Afghan War in 1919, Afghanistan became free of foreign political hegemony, and emerged as the independent Kingdom of Afghanistan in 1926. This monarchy lasted almost half a century, until Zahir Shah was overthrown in 1973, following which the Republic of Afghanistan was established.

The Gowd-i zerrah, i.e., Zerrah Depression (Persian for "lake depression") is the lowest part of an inland drainage basin covering large parts of southern Afghanistan and Iran known as the Sistan Basin. The Sistan Basin is an endorheic basin and encompasses a complex system of rivers, shallow lakes, marshes, and wetlands as its watershed, draining into the Hamun Lakes in southeastern Iran. Occasional outflows from these lakes are carried back into Afghanistan by the seasonal Shile River to the basin's terminus, the Godzareh depression in Afghanistan. The depression is flat and very shallow with fine-textured sediment at its lowest portions. The lowest section of the Godzareh depression is 467 m above sea level. The depression only receives runoff water when the main tributaries are overflowing every 10 years on average.

In general, a geological depression is a landform that is sunken or lower than the surrounding area. The Godzareh depression is the lowest point in the Sistan Basin in Afghanistan and therefore is the terminus to which all the water flows.

Lake Hāmūn (Persian: دریاچه هامون, Daryāche-ye Hāmūn; Pashto: هامون ډنډ), or the Hamoun Oasis, is a seasonal lake and wetlands in the endorheic Sīstān Basin in the Sistan region on the Afghanistan–Iran border. In Iran, it is also known as Hāmūn-e Helmand, Hāmūn-e Hīrmand, or Daryāche-ye Sīstān ("Lake Sīstān").

Hāmūn is a generic term for shallow lakes (or lagoons), usually seasonal, that occur in the deserts of southeast Iran and adjacent areas of Afghanistan and Pakistan as a product of snowmelt in nearby mountains in spring. The term Hāmūn Lake (or Lake Hāmūn) equally applies to Hāmūn-e Helmand (entirely in Iran), as well to the shallow lakes Hāmūn-e Sabari and Hāmūn-e Puzak, which extend into the territory of present-day Afghanistan with the latter almost entirely inside Afghanistan.

Afghanistan, officially the Islamic Emirate of Afghanistan, is a landlocked country located at the crossroads of Central and South Asia. It is bordered by Pakistan to the east and south, Iran to the west, Turkmenistan to the northwest, Uzbekistan to the north, Tajikistan to the northeast, and China to the northeast and east. Occupying 652,864 square kilometers (252,072 sq mi) of land, the country is predominantly mountainous with plains in the north and the southwest, which are separated by the Hindu Kush mountain range. Kabul is the country's capital and largest city. Afghanistan's population is estimated to be between 40 and 50 million.

Human habitation in Afghanistan dates to the Middle Paleolithic era. Popularly referred to as the graveyard of empires, the land has witnessed numerous military campaigns, including those by the Persians, Alexander the Great, the Maurya Empire, Arab Muslims, the Mongols, the British, the Soviet Union, and a US-led coalition. Afghanistan also served as the source from which the Greco-Bactrians and the Mughals, among others, rose to form major empires. Because of the various conquests and periods in both the Iranian and Indian cultural spheres, the area was a center for Zoroastrianism, Buddhism, Hinduism, and later Islam. The modern state of Afghanistan began with the Durrani Empire in the 18th century under Ahmad Shah Durrani, although Dost Mohammad Khan is sometimes considered to be the founder of the first modern Afghan state. Afghanistan became a buffer state in the Great Game between the British Empire and the Russian Empire. From India, the British attempted to subjugate Afghanistan but were repelled in the First Anglo-Afghan War; the Second Anglo-Afghan War saw a British victory. Following the Third Anglo-Afghan War in 1919, Afghanistan became free of foreign political hegemony, and emerged as the independent Kingdom of Afghanistan in 1926. This monarchy lasted almost half a century, until Zahir Shah was overthrown in 1973, following which the Republic of Afghanistan was established.

Drangiana or Zarangiana (Greek: Δραγγιανή, Drangianē; also attested in Old Western Iranian as 𐏀𐎼𐎣, Zraka or Zranka, was a historical region and administrative division of the Achaemenid Empire. This region comprises territory around Hamun Lake, wetlands in endorheic Sistan Basin on the Iran-Afghan border, and its primary watershed Helmand river in what is nowadays southwestern region of Afghanistan.