1Isaac Briggs to Thomas Jefferson, 21 May 1817 (Jefferson Papers)
”; franked; postmarked Washington City, 21 May.
2To Thomas Jefferson from Isaac Briggs, 20 October 1808 (Jefferson Papers)
Washington City 20 of the 10 mo 1808.
3To Thomas Jefferson from Isaac Briggs, 9 January 1807 (Jefferson Papers)
Washington City 9 of the 1 mo 1807
4Isaac Briggs to Thomas Jefferson, 16 February 1816 (Jefferson Papers)
...exploring and ascertaining the topography of a Post-route from Washington City to
5Isaac Briggs to Thomas Jefferson, 30 March 1816 (Jefferson Papers)
Washington City,
6Isaac Briggs to Thomas Jefferson, 7 May 1816, with Postscript by Mary B. Briggs (Jefferson Papers)
...present residence, during a second journey I have made to Washington City. I returned yesterday.