Sungei Serangoon is a river in the north-eastern part of Singapore. The 8-kilometre river starts as a canal near Tampines Road, and flows through Hougang, where it is joined by tributary Sungei Pinang just before Sengkang, before flowing towards Lorong Halus, where it is joined by another tributary Sungei Blukar, before emptying into the Serangoon Harbour. The river is also known as the Serangoon Estuary. Since 2011, the river has been converted into a reservoir - Serangoon Reservoir.