This is the official map of Washington City (later Washington, DC) engraved in 1820 by W.I. Stone.  This map appears to be an updated version of the 1818 map produced by Robert King.  Stone's map includes George Town (sic) and a more detailed north shore of the Eastern Branch.  That this map was again updated in 1829 seems to be decent evidence of its qualification as ephemera.

This map could be an excellent resource to teach students the thematic strand of people, places, and the environment by identifying where the Potomac has been filled in to create part of the mall; evidence of humans changing their landscape even in the 1800s.  Students could also study the layout of Washington, DC as a way of better understanding power, authority, and governance.  Where are the buildings that house each of the three branches of government?  Why are the streets laid out like they are?  By comparing this map to a more contemporary map of DC, students could discuss time, continuity, and change.