Isaac Dutton Barnard (July 18, 1791 – February 28, 1834) was an American militia leader, lawyer, and politician who served as a United States Senator for Pennsylvania from 1827 to 1831.

[4] At age 20, Barnard received a commission as Captain of the Fourteenth Regiment, United States Infantry.

He fought in the War of 1812 and saw action at Baltimore, Sackett's Creek, the Canadien Frontier, Fort George, La Cole's Mill, the battle of Crysler's Farm, the Battle of Plattsburgh and Lyon's Creek.

[4] He was elected to the United States Senate as a Jacksonian, and began his first term on March 4, 1827.

[8] Just before he resigned, the New York papers were reportedly demanding that Barnard be given a place in the United States Cabinet.

He was originally interred at the Friends Burying Ground on North High Street but after twenty years he was re-interred in Oaklands Cemetery.