Hāmūn-e Helmand (also known as Hāmūn-e Hīrmand, “Lake Hāmūn”, Hamoun Oasis, Persian: دریاچه هامون‎ Daryācheh-ye Hāmūn or Daryācheh-ye Sīstān (“Lake Sīstān”)) is a shallow, marshy, lake (or lagoon) or hāmūn located in the Sistan region of eastern Iran and western Afghanistan. It is fed by the Helmand River, which starts in the Hindu Kush mountains in Afghanistan.