The transboundary water dispute between Iran and Afghanistan is historical. Both neighbouring countries have been dealing with the water-sharing dispute somewhat without progressing towards a permanent solution. The problem is centred around the Helmand River, which starts from the Hindu Kush Mountains near Kabul and streams into Iran's Hamoon wetlands in Sistan and Balochistan province (southeast of Iran). This river was defined as the territory of Iran. Until 1857, Herat was part of Iran, and only after Iran and Britain signed the Paris Treaty of 1857 did Iran abandon its claim.