It is located 25 kilometres (16 mi) south of Blenheim, close to the mouths of the Awatere and Blind Rivers and the Lake Grassmere salt works.

[3][4] Salt and lime[5] are major local industries, and the Awatere Valley is an important part of the Marlborough wine region.

[11] First, in late July, a series of sizeable earthquakes struck the region over a period of a few days being felt strongly in Blenheim, Wellington and the rest of Central New Zealand, the strongest being a magnitude 6.5 and having its epicentre in Cook Strait.

The Marlborough section of the Main North Line railway reached Seddon from Blenheim in October 1902.

[17] This also saw the construction of a combined road-rail bridge over the Awatere River north of the town, with the single-lane road below the rail.

[17] Today, Seddon is served by the Coastal Pacific train, which runs once daily each way during the summer months.