David H. Burr (1803–75) was a surveyor and cartographer, who served as topographer to the United States Post Office Department in 1832–38 and as geographer to the House of Representatives in 1838–47. Under the direction of the postmaster general, Burr compiled information from postmasters throughout the country about transportation routes—post roads, railroads, and canals—and the location of post offices to produce a large set of state and regional maps. Published in 1839 by the prominent London mapmaking firm of John Arrowsmith, Burr’s The American Atlas offers a detailed picture of settlement and transportation patterns in the United States in the decades before the Civil War. Shown here is Burr’s map of Virginia, Maryland, and Delaware, one of 13 maps in the atlas. Virginia includes the 41 counties in the northwestern part of the state, which later chose not to secede from the Union and which in 1863 became the separate state of West Virginia. The map shows the early development of the port city of Baltimore as a railroad junction and terminus.