This broadens to wide plains at its eastern end, in the centre of which stands the town of Blenheim.

This region has fertile soil and temperate weather, which has enabled it to become the centre of the New Zealand wine industry.

Here, the drowned valleys of the Marlborough Sounds make for a convoluted and attractive coastline.

In line with most of New Zealand, the Marlborough Region has a temperate oceanic climate (Köppen Cfb) with warm summers, cool winters, and rainfall distributed across the year.

As of October 2022, the mayor and councillors are:[15] Nationally, Marlborough is part of the Kaikōura electorate, which also includes the Canterbury region north of the Ashley River / Rakahuri.

For the Māori roll, Marlborough is part of the Te Tai Tonga electorate, as is the entire South Island.

Stuart Smith of the National Party has been the MP for the Kaikōura electorate since the 2014 general election.

[19] Marlborough has 25,045 hectares (61,890 acres) of horticultural land as of 2017, the second-largest area in New Zealand behind Canterbury.

[20] The ripening period of wine grapes is extended by Marlborough's climate, which has a strong contrast between hot sunny days and cool nights.

The first commercial vineyards were planted around Blenheim in 1973, and Marlborough subsequently grew to become New Zealand's largest and most internationally well-known wine-producing region.

[23][24] Also, important is the production of méthode traditionelle sparkling wine made from Chardonnay and Pinot Noir, which has attracted investment from large Champagne producers Mumm, Deutz, Moët & Chandon and Veuve Clicquot.

The Waihopai communications monitoring facility, run by the Government Communications Security Bureau (GCSB) and part of the ECHELON network, is located in the Waihopai Valley 11 km (7 mi) southwest of Renwick.

State Highway 63 leaves State Highway 6 at Renwick and travels via the Wairau Valley and Saint Arnaud to meet SH 6 again at Kawatiri, providing a direct route to the West Coast and bypassing Nelson.

The Main North Line railway serves the region, running roughly parallel to State Highway 1.

The line south of Blenheim opened to Seddon in October 1902, to Ward in April 1911, and to Wharanui in December 1915.

[26] Today, the line is used by the Coastal Pacific passenger train, which operates one return journey per day during the summer months.

The line is also heavily used by freight trains between Christchurch and the Cook Strait rail ferry at Picton.