The Topographical Engineering Corp. 1831-1863.

The independent Topographical Engineering Bureau was established in 1831.
The smallest branch in the Army, it was first led by colonel John Abert till 1861, then by colonel Stephen Long.
It was absorbed by the Army Engineering Corp, by an act of congress in 1863.
In spite of its low headcount (some 44 officers on the eve of the Civil War), the Corp amassed an impressive cartographic knowledge. It was instrumental in facilitating:
- the taming of the western and southern territories,
- the conduct of operations during the second Seminole war between 1836 and 1843,
- the prosecution of the war with Mexico between 1846 and 1848,
- the strategic and tactical moves during the Civil War, between 1861 and its demise in march 1863.

Map of Santiago de Cuba and vicinity.

This topographical map (10 9/16" X 7 3/8") was produced by the Lt. Col. G McDerby of the Army Engineering Corp to illustrate the encirclement of Santiago by the American forces during the war with Spain.
After the Spanish naval forces annihilation on July 3 1898, the spanish defenders were desperate. While inflicting severe casualties to the invaders, they could not but surrender on July 17th. The map shows the respective land forces positions a few days before the end of combats.
East of the city is the small hill of San Juan where Theodore Roosevelt achieved fame and glory. An assistant secretary of the Navy, he had accepted the command of a volunteer regiment, the "rough riders'. On July 1st he led his men up the hill and took it, opening up the Spanish defensive system to the fire of american guns from that position.
No text on verso.