Blenheim (/ˈblɛnɪm/ BLEN-im; Māori: Waiharakeke[2]) is the most populous town in the region of Marlborough, in the north east of the South Island of New Zealand.

The New Zealand Ministry for Culture and Heritage gives a translation of "flax stream" for the town's Māori name, Waiharakeke.

[3] The sheltered coastal bays of Marlborough supported a small Māori population possibly as early as the 12th century.

In the early 1700s canals and waterways were dug among the natural river courses, allowing for the first forms of farming in the area including that of fish and native water fowl.

Situated on the Wairau Plain, the town is mostly flat with only its southernmost fringe rising to the base of the Wither Hills.

As the plain is surrounded by mountains on all but the eastern flank, which is open to Cook Strait, it is relatively well protected from the frequent southerly weather fronts occurring during winters.

Open and exposed areas in and around Blenheim are also hit quite hard by winds blowing inland from Cook Strait.

Snowfall is rare as the town is sheltered from cold southerly weather by the mountain ranges to the south.

The town's economy is based on agricultural services, with pastoral and horticultural farming providing a major source of income.

Marlborough's first commercial grape vines were planted in 1973, and since then viticulture has become the dominant industry in the region; employment is derived not only from the production of wine, but also from 'wine tourism' in the area.

Despite being located several kilometres inland, maritime industries are also important sources of employment for Blenheim.

Viticulture also has a very large impact on the local economy both directly, by way of employment and servicing required, and also by way of 'wine tourism'.

With its growing international critical recognition, much of the Marlborough wine industry has come to be dominated by large firms, owned by major New Zealand companies or offshore investors.

Rapid population growth and other factors though have led to a contemporary chronic shortage of affordable housing for low and middle income earners.

Omaka Aerodrome, south of the town centre, is the setting for the two-yearly Classic Fighters Marlborough airshow.

Seymour Square and Pollard Park are two of the town centres main attractions for walks and general tourism.

The Classic Fighters airshow (based mainly on World War I and II aircraft) is held biennially at Easter.

The Coastal Pacific, a long-distance passenger train between Picton and Christchurch, stops at Blenheim railway station.

Blenheim's water supply is drawn from the Wairau aquifer via nine bores and is treated at two plants in Middle Renwick Road and Bomford Street.

[27] An intention to relocate both Marlborough Boys' College and Marlborough Girls' College on the site currently occupied by MGC and Bohally Intermediate was announced in 2019, with Bohally Intermediate relocating to the current MBC site on Stephenson Street.

The major daily newspaper serving the area is The Marlborough Express published by Fairfax NZ, with its headquarters in Blenheim.

The Blenheim Sun is a twice-weekly free newspaper distributed each Wednesday and Friday while the locally owned Marlborough Weekly is published every Tuesday and delivered to every home in the region.

The town can also receive AM and FM radio stations from Wellington, due to the straight line-of-sight across Cook Strait and the high power of the transmitters.