William Claiborne was the second son of Thomas and Sara Claiborne of Crayford in Kent. He was baptized at Crayford on August 10, 1600. He attended Cambridge University in 1617 and in 1621 was appointed by the Virginia Company to be their surveyor for three years. Sailing on the ship George, he arrived in Jamestown in October. By 1625, Charles I had appointed him to the council and named him Virginia Secretary of State.

Claiborne recognized the profit in the fur trade and as early as 1626 was proposing to extend trade with the Indians in the Chesapeake. This took on more urgency when George Lord Baltimore arrived in Jamestown in 1629 seeking land for a more hospitable colony than Ferryland. On May 16, 1631, Charles I granted Claiborne a patent for trading privileges with the Indians. Using this patent, Claiborne set up a trading company with William Cloberry and other London merchants. Their trading post was on Kent Island and Claiborne acted as the chief agent. The enterprise prospered until the arrival of Lord Baltimore's colony in 1634.

Hostility between the two groups was evident even before the founding of St. Mary's City and increased violently due to competition for the fur trade. In Pocomoke Sound, on April 23, 1635, there was a confrontation in which the Marylanders had a man killed and several wounded while the Kent Islanders lost three men. Both sides seized the trading goods and vessels of the other when they could. Dissatisfied with the situation, Cloberry & Co. sent George Evelyn to displace Claiborne in 1637. After securing Evelyn's promise not to recognize the authority of the Marylanders, Claiborne went to England to argue with his partners and to seek help from the Crown. Soon thereafter, Evelyn acknowledged Baltimore's claim and, after an invasion led by Thomas Cornwaleys, Kent Island became part of Maryland.

Although Claiborne was never able to get the Crown to support his claims, he kept a strong interest in Kent Island. In 1644, he attempted to aid Richard Ingle in his rebellion against Lord Baltimore's government. He was unsuccessful in raising the Kent Islanders against the government. This rebellion ultimately failed but in England, the victory of Parliament over the king gave him another opportunity. On September 26, 1651, Claiborne was appointed one of the Parliamentary commissioners for reducing the plantations of the Chesapeake into submission to the Parliament. For a brief period, Claiborne was able to reassert his claim to Kent Island.

However, Lord Baltimore made his peace with Cromwell's government and by 1658, there was an agreement to restore the province and government to him. Claiborne had lost Kent Island for the last time. With the Restoration of Charles II, Claiborne also lost his offices in the Virginia government. He settled down to manage his estates in Virginia. In 1677, Claiborne and his son, William Jr., made one last attempt to regain title to Kent island. They petitioned the Royal Commissioners appointed to settle Virginia after Bacon's Rebellion. This attempt failed also and William Claiborne died soon thereafter.

Fausz, J. Frederick. "Merging and Emerging Worlds: Anglo-Indian Interest Groups and the Development of the Seventeenth-Century Chesapeake." in Lois Green Carr, Philip D. Jordan, and Jean B. Russo, eds. Colonial Chesapeake Society. Chapel Hill: University of North Carolina Press, 1988.

_____. "Present at the 'Creation": The Chesapeake World that Greeted the Maryland Colonists." Maryland Historical Magazine. 79 (1984): 7-20.

Hale, Nathaniel C. Virginia Venturer: A Historical Biography of William Claiborne, 1600-1677. Richmond, Va.: The Dietz Press, Inc., 1951.

Hall, Clayton Colman, ed. Narratives of Early Maryland, 1633-1684. New York: Barnes & Noble, Inc., 1910.

Isaac, Erich. "Kent Island: Part I: The Period of Settlement." Maryland Historical Magazine. 52 (1957): 93-119.