Giles County was established in 1809 and named in honor of Senator William B. Giles of Virginia, one of the strongest advocates for the admission of Tennessee to the Union; he served in the U.S. Senate from 1804 to 1815 and was Governor of Virginia from 1827 to 1830. Marshall County was established in 1836 and named in honor of John Marshall of Virginia, who was serving in Congress in 1799, was Secretary of State from 1800 to 1801, and was Chief Justice of the United States from 1801 to 1835.