The Henry family were armsmakers who operated a family gun manufactory in eastern Pennsylvania for five generations.

The business was founded by the first William Henry (1729-1786), the son of John Henry, an early immigrant from Ireland. In 1744 William moved to Lancaster, Pennsylvania, where he was apprenticed to a gunsmith. He soon achieved great expertise in the craft, and from 1750 to 1760 he conducted the business in partnership with Joseph Simon (1813-1888), a merchant and Indian trader. During the Indian wars from 1755 to 1760, Henry served as the principal armorer for the colonial troops. After 1760 he conducted business alone. The Henry rifle, the prototype of what later became known as the Kentucky rifle, was famous for its quality.

William Henry also served as Treasurer of Lancaster County from 1777 until his death; as Assistant Commissary General and Disbursing Officer for the District of Lancaster County during the Revolutionary War; and as a delegate to the Continental Congress in 1784. He joined the American Philosophical Society in 1768, along with his close friend, David Rittenhouse. He invented a screw augur, a steam-heating system, a "sentinel register" for regulating the flue damper in furnaces, and is often credited with trying to develop a steamboat. He died in Lancaster on December 15, 1786.

Three sons of William Henry carried on the family tradition of gunmaking. Abraham Henry (d. 1811) and John Joseph Henry (1758-1811) continued to work in Lancaster. William Henry, Jr., (1757-1821) apprenticed under his father and opened his own rifle-making shop at the Moravian community of Christian Spring, Pennsylvania in 1778. In 1780 he moved to nearby Nazareth. Like his father, he was involved in local politics and was made justice of the peace and associate judge of the Court of Common Pleas of Northampton County. He was involved in the early operations of the Lehigh Coal Mine Company (1792-1798), and for a while was its chief agent in the field. Around 1794 he laid out the town of Lehighton, Pennsylvania with Charles Cist. His son, Matthew Schropp Henry (1790-1862) became an ironmaster and built the Catharine Furnace nearby. M. S. Henry also wrote a history of the Lehigh Valley and a dictionary of the Delaware Indian language.

William, Jr., brought his other two sons, John Joseph (1786-1836) and William (1794-1878), into the business. John Joseph moved to Philadelphia in 1808, where he set up a branch gun shop and handled sales for the works at Nazareth. William was sent to Philadelphia as an apprentice to his older brother.

In 1808, William Henry, Jr., contracted to supply the U.S. government with 10,000 muskets and bayonets at a fixed price of $10,750, payable in advance. The arms were to be delivered at the rate of 2,000 per year. The government furnished the patterns, but the inspector rejected the first shipment and demanded changes, which Henry complied with. In 1812-1813, Henry constructed a much larger factory, the Boulton Gun Works, on Bushkill Creek at nearby Jacobsburg in anticipation of war orders and William, III, returned to supervise the work. However, the controversy with the government deepened. The alterations requested increased the costs to the Henrys to below profitability, and the cost of the Boulton Works constituted an additional burden. Eventually, William, Jr., refunded the entire advance. The government also blocked the Henrys from receiving further government contracts, although they did get orders for the state militias of Maryland and Delaware. In March 1817 William, Jr., retired to Philadelphia and sold the works to his two sons.

William, III, continued to operate the works, while John Joseph remained in Philadelphia, but the firm was further hurt by the depression of 1819. The brothers finally won some partial compensation from the government in 1820-1821. In 1822 William sold his interest to John Joseph, who came up from Philadelphia. John Joseph achieved a limited prosperity, primarily supplying rifles to Astor's American Fur Company. At his death in 1836, the works passed to his son, James (1809-1894). Regular operations ceased in 1895, although his son, Granville Henry (1834-1912), maintained the property during his lifetime.

William Henry, III, then operated a store at Wind Gap, Pennsylvania from 1822 to 1828. He then joined with his nephew, John Jordan, Jr., to build Analomink Forge, which was to refine iron made by his brother Matthew's furnace. The brothers quarreled, and in 1832 William took a lease on Oxford Furnace in New Jersey to secure a supply of pig iron. He later brought his son-in-law, Selden T. Scranton (1814-1891), into this operation. Henry spent a great deal of time promoting railroads to open the territory and in experimenting with smelting iron with anthracite coal. He designed the first Lackawanna furnace during 1840 and 1841, but was blamed by his partners, the Scrantons, for its failure and forced out of the venture in 1842. He spent the remainder of his life in a series of minor jobs, often on charity from his former partners and relatives.