Historic Marker number 111 is located at the corner of Whitehead and Front Streets.Construction of this imposing brick structure began in 1856 and was completed in 1861. Even though the present day building is identified as the Coast Guard Headquarters, it began as the U.S. Navy Coal Depot & Storehouse, Building # 1. The historic functions of the building were defense, commerce, trade, warehouse, and naval administration until 1932. During the Civil War, the Union’s West Indies Blockade Squadron was headquartered here. The blockade is credited with shortening the Civil War and saving countless numbers of soldiers on both sides of the nationwide conflict.One of the structures greatest assets, in the 1800s, was as a coal depot. .The U.S. Navy began to convert its fleet from sailing ships to steam powered vessels in the 1840s. Sail transportation was quickly outmoded as the reliability of steam engines improved and iron hulled, screw-propelled ships were developed. Steel hulled ships could be built substantially larger and longer than their wooden counterparts. The only downside of a steamship was the need for large amounts of coal to keep the boiler furnaces stoked.Key West was a strategic coaling location for steamships embarking on Trans-Atlantic, Caribbean, or South America voyages as evidenced by the numerous coal sheds lining the harbor in the mid-1800s.Initially, coal was shoveled into bins and pushed along piers to waiting steam ships where it was shoveled onboard. As the need for coal increased, it was moved from shoreline storage facilities on large aerial conveyor belts to a coal transfer station suspended over the harbor waters. Ships were able to transfer coal from the harbor station quicker and with less manual labor. The second floor of the navy building was reserved for sail makers. As the use of steamboats made inroads into traditional sail powered ships, the need for a good sail remained. The irony of many of the early steamboats is that they were outfitted with rigging and sails to augment steam power and as a safeguard in the advent that steam propulsion failed.In 1932, the offices of the 7th Lighthouse District opened in this building. Their duties included overseeing Florida Keys lighthouses, light ships, and channel markers. By 1939, the U.S .Coast Guard changed the name of the building from the Naval Coal Depot to the Coast Guard Headquarters to depict their use of the building. The Coast Guard Headquarters building was added to the National Register of Historic Places in 1973 and remains Key West’s oldest brick structure.