Panama Canal Zone
The Panama Canal Zone () was an unincorporated territory of the United States from 1903 to 1979, centered on the Panama Canal and surrounded by the Republic of Panama. The zone consisted of the canal and an area generally extending on each side of the centerline, excluding Panama City and Colón, which otherwise would have been partly within the limits of the Zone. Its border spanned three of Panama's provinces. When reservoirs were created to assure a steady supply of water for the locks, those lakes were included within the Zone.
Panama Canal
In 1846, the Mallarino–Bidlack Treaty, negotiated between the US and New Granada, granted the United States transit rights and the right to intervene militarily in the isthmus. In 1848, the discovery of gold in California, on the West Coast of the United States, created great interest in a crossing between the Atlantic and Pacific oceans. William H. Aspinwall, the man who won the federal subsidy for the building and operating the Pacific mail steamships at around the same time, benefited from this discovery. Aspinwall's route included steamship legs from New York City to Panama and from Panama to California, with an overland portage through Panama. The route between California and Panama was soon frequently traveled, as it provided one of the fastest links between San Francisco, California, and the East Coast cities, about 40 days' transit in total. Nearly all the gold that was shipped out of California went by the fast Panama route. Several new and larger paddle steamers were soon plying this new route, including unsubsidized steamship lines owned by Cornelius Vanderbilt that required an overland route through Nicaragua.