The Athenian River, also known as the Ilissos, is a river in Athens, Greece. It flows through the city and is historically significant, as it was a vital water source for the ancient Athenians. The river is approximately 20 kilometers long and has its origins in the Mount Hymettus region. In ancient times, the Athenian River was associated with various myths and cultural practices. It was often linked to the worship of Apollo and served as a gathering place for citizens. Today, parts of the river are covered or diverted, but its historical importance remains a point of interest for visitors and scholars alike.