Tuamarina is a small settlement at the southern entrance of Waitohi valley on State Highway 1 between Blenheim and Picton. Tuamarina is a corruption of Tuamarino 'the calm beyond'. The name comes from when Rangitane explorers travelling through the thick, near impenetrable jungle of Para came to a hill at the end overlooking the Wairau plain. The leader exclaimed to his men following " Calm Beyond!" This is somewhat ironic as a hundred or more years later Te Rauparaha and other Maori killed over forty Europeans on Whiringatou in the same place as the result of a land dispute that escalated out of control. For many years Tuamarina was the site of a cheese factory making the Waitohi and Koromiko brands, however after a fire that caused severe damage, the factory was closed.
The settlement has a primary school and a community hall. A monument to the Europeans killed in the land dispute reported at the time as "The Wairau Massacre" but now referred to in somewhat less emotive terms as "The Wairau Incident" sits on the hill above the settlement.
To the west of the settlement across State Highway One, is the Tuamarina River which drains the Para wetland into the Wairau River. Near the river is a small reserve with a stone monument erected to commemorate 100 years of the Marlborough District in 1959.