Brigadier-General William Cosby (1690 – 10 March 1736) was a British Army officer and colonial administrator who served as the governor of New York from 1732 to 1736.

In spite of Cosby's efforts, Zenger was acquitted of all charges and the case helped to establish the concept of freedom of the press.

His administration was unremarkable in most respects, but he ran into difficulties when he illegally seized a Portuguese ship and attempted to appropriate its valuable cargo of snuff for his own benefit.

On 13 January 1732, George II appointed Cosby as "Captain General & Governor in Chief of the Provinces of New York, New Jersey and Territories depending thereon in America".

On 2 January 1734, King George II granted Cosby 22,000 acres on the Mohawk River, in what is now Herkimer County, New York.

Chief Justice Lewis Morris, aware of public opinion, dismissed Cosby's case on legal grounds on 9 April 1733.

He also dismissed Van Dam from the provincial council and named loyalist James De Lancey the new chief justice.

In New York, the Septennial Act of 1743 ensured that assembly elections would henceforth be held at regular intervals, no less than once every seven years.

[6]: 209–210 As governor, Cosby illegally seized lands owned by colonists in Hopewell, New Jersey, awarding them to his royalist allies, Dr Daniel Coxe and his son.

Cosby pushed out the settlers, forcing them to repurchase their properties, and then, as supreme judicial official of the colony, rejected the popular pleas led by Lewis Morris.

Ensconced in his own world of self-enrichment and political repression, Cosby neglected his duties in frontier affairs.

Its mordant editorials were mainly written by socially notorious people, Morrisites like James Alexander, who published anonymously.

The principle he proclaimed still stands in modern United States law: libel only exists when falsehoods are perpetrated.

[6]: 206 Cosby died of tuberculosis on 10 March 1736, between 1 and 2 pm, in the Governor's House at Ft. George, today's Battery Park, New York City.

He frustrated Van Dam's aspirations again, starting another political scandal, even before official confirmation of his appointment by the Crown.

Eighteenth-century observers believed that Governor William Cosby was motivated by two goals: defending British interests and building his private fortune.

[6]: 202 Although Cosby's governorship was not a rewarding period for colonial New York, the struggles of the 1730s ultimately helped define the roles of the governor, the assembly, and the courts in provincial politics.

Once the structural problems were addressed, politicians could turn their attention to the substantive issues and engage a larger portion of the population in political activity.