Here is a county map of the US circa 1860.
Desciption on the LOC (Library of Congress) website.
“””””””””””July 4, 1861
On April 15, 1861, President Abraham Lincoln issued a proclamation calling for the initial raising of 75,000 militia to begin preparations for the upcoming armed conflict between Union and Confederate armies. In the same proclamation, Lincoln called for an extra session of Congress to discuss the war which would meet on July 4, 1861:
“Now, therefore, I, ABRAHAM LINCOLN, President of the United States, in virtue of the power in me vested by the Constitution and the laws, have thought fit to call forth, and hereby do call forth, the militia of the several States of the Union…I deem it proper to say that the first service assigned to the forces hereby called forth will probably be to repossess the forts, places, and property which have been seized from the Union…. [and[ deeming that the present condition of public affairs presents an extraordinary occasion, I do hereby, in virtue of the power in me vested by the Constitution, convene both Houses of Congress. Senators and Representatives are therefore summoned to assemble at their respective chambers, at twelve o’clock noon, on Thursday, the fourth day of July next, then and there to consider and determine such measures as, in their wisdom, the public safety and interest may seem to demand.”
The purpose of the extra session was for lawmakers to debate raising troops to defend the Union and to appropriate funds for the prosecution of the war. In the summer of 1861, commercial publishers like Charles Magnus updated existing maps with updated phrases such as “Extra Session of Congress Map” to make their maps appear more relevant to the shifting headlines.””””””””””””