(1763–1829) military engineer. Son of Daniel Roberdeau, Isaac was born in Philadelphia and studied engineering. He was an assistant (1791–92) to Pierre Charles L'Enfant, who laid out the design for Washington, D.C., and was frequently caught up in disputes between the city's commissioners and L'Enfant, one of which resulted in Roberdeau's arrest for refusing to stop digging the foundations for the Capitol building, despite having been dismissed by the commissioners; Roberdeau said he took orders only from L'Enfant. When the War of 1812 erupted, he became a major in the Topographical Corps of Engineers. He helped survey part of the boundary between the United States and Canada (1815).In 1818 he became the Corps' chief.
From The Oxford Essential Dictionary of the U.S. Military in Oxford Reference.
Subjects: Warfare and Defence.