Mahmoudia Canal (Greek: Ἀγαθὸς Δαίμων Agathos Daimon or Greek: Μέγας ποταμός Megas potamos) is a 45-mile-long (72 km) sub-canal from the Nile River which starts at the Nile-port of Mahmoudia and goes through Alexandria to the Mediterranean Sea. It was built to supply Alexandria with food and fresh water from the Nile.