James Cannon (1740–1782) was a Scottish-born American mathematician, and one of the principal draftsmen of the 1776 Constitution of the State of Pennsylvania.
Born in Edinburgh in 1740, Cannon was educated at the University of Edinburgh and moved to Pennsylvania to continue his studies at The Academy and College of Philadelphia, now the University of Pennsylvania. He graduated with a B.A. in 1767 and returned in 1773 as a Professor of Mathematics, a position he held until his death in 1782. when he died his family continued in his work.
During the American Revolution, Cannon was one of the leaders of a radical faction campaigning for independence, in opposition to Philadelphia's majority support for an accommodation with Britain. The radical group included Cannon, George Bryan, Timothy Matlack, Thomas Young and Thomas Paine.
Cannon was a founder of the Philadelphia Society for the Promotion of American Manufactures, which organized citizens of Philadelphia in making woolen, linen and cotton fabrics. According to Christopher Marshall's diary, Cannon was a leading organizer in private meetings held to select radical candidates for the 1776 elections to the Pennsylvania Provincial Assembly.
The moderate faction won a majority in the elections on May 1, 1776, but were outmaneuvered by the radicals, who successfully persuaded the Continental Congress to resolve that all local governments deriving their authority from the British Crown should be "totally suppressed." This resolution hastened the end of British authority in the United States and effectively undermined the Charter and Assembly of Pennsylvania.