William Henry has been the name of several notable men:

• William Henry, (1729-1786), U.S. gunsmith, Pennsylvania delegate to Continental Congress
• William Henry, (1775-1816), English chemist who formulated Henry’s law
• William Henry, Classicist/Ancient Historian
• William Henry, (1788-1861), U.S. Congressman from Vermont
• William Henry, (1859-?), British swimmer
• Wiliam Henry, (1918-1982), U.S. movie actor
• William Henry Hastie (1904-1976), the first African American federal judge

It is also the name of the father of Joseph Henry.

There is also:

• William III of England is sometimes known as "William Henry, Prince of Orange" as a translation of his Dutch title "Willem Hendrik, Prins van Oranje"
• William IV of England was known as "William Henry, Duke of Clarence" before he became king.
• William Alexander Henry, (1816-1888), justice of the Canadian Supreme Court

As a location:

• William Henry was the original name for the town of Sorel, Quebec

William Henry