The design and construction of the New River is often attributed to Sir Hugh Myddelton(or Myddleton)*.  Edmund Colthurst first proposed the idea in 1602, obtaining a Charter from King James I in 1604 to carry it out.  After surveying the route and digging the first 2-mile stretch, Colthurst encountered financial difficulties and it fell to Hugh Myddelton to complete the work between 1609 and its official opening on 29 September 1613.  The project was also rescued by King James whose house and lands at Theobalds Park, were crossed by the river.  King James took half of the shares in 1612 for half of the profits.  In order to give the Project a firmer legal and financial structure, The New River Company was incorporated in 1619 by Royal Charter, with the assistance of Sir John Backhouse.  The company's first reservoir was built on his land in Islington.  Myddelton gave some of the shares in the New River Company to Edmund Colthurst.

The expense and engineering challenges of the Project - it relied on gravity to allow the water to flow - carefully following the contours of the terrain from Ware into London, and dropping around just 5 inches per mile (8cm/km) - were not Myddelton's only worries.  He also faced considerable opposition from landowners who feared that the New River would reduce the value of their farmland - they argued that floods or overflowing might create quagmires that could trap livestock.  Others were concerned about the possible disruption to road transport networks between Hertfordshire and the Capital. 

The Project nearly foundered when a few landowners flatly refused to agree to allow the river across their land.  At the time, it was proposed that the development of a College in Chelsea, which was a project of King James, would be funded by the proceeds of a rival project to support water to London.  After that project failed, Myddelton was eventually strongly supported by the King, who agreed to pay half of the Project's expenses, in return for a 50% shareholding.

When it was originally constructed, long sections - for example around Forty Hall and in Hornsey - wound around the heads of small tributary valleys of the Lea.  Other sections of the river, including the one in Harringay, were carried across valleys in wooden aqueducts, lined with lead and supported by strong timbers and brick piers. In at least one section, locals referred to the river as the 'boarded river'.  Improvements in canal construction in the 18th Century led to these sections being replaced by clay-baned canals.

On 09 January 1622, King James rode from Theobalds to see the ice on the New River and fell in headfirst, so that companions could only see his boots!.  He was rescued by Sir Richard Young.

The spelling of Sir Hugh's name is inconsistently reproduced, but Myddelton appears to be the earliest, and most consistently used in place names associated with him