The Clarence River is on northeast South Island of New Zealand. It is 230 kilometres (140 mi) long, the eighth longest river in New Zealand

For its first 50 kilometres, the river runs in a generally southeastern direction. It then turns northeast, running down a long straight valley between the inland and seaward Kaikoura Ranges. At the end of the seaward Kaikouras, the river meanders through undulating hill country before draining into the Pacific Ocean near the town of Clarence. A large part of the river is within the boundaries of Molesworth Station.