The Isthmus of Panama runs east and west and the canal traverses it from Colon on the north to Panama on the south in a general direction from northwest to southeast, the Pacific terminus being twenty-two miles east of the Atlantic entrance. The principal features of the canal are a sea-level entrance channel from the east through Limon Bay to Gatun, about seven miles long, five-hundred-foot bottom width and forty-one-foot depth at mean tide. At Gatun the eighty-five-foot lake level is obtained by a dam across the valley. The lake is confined on the Pacific side by a dam between the hills at Pedro Miguel, thirty-two miles away. The lake thus formed has an area of 164 square miles and a channel depth of not less than forty-five feet at normal stage.

At Gatun ships pass from the sea to the lake level, and vice versa, by three locks in flight. On the Pacific side there is one lowering of thirty feet at Pedro Miguel to a small lake fifty-five feet above sea level, held by dam at Miraflores, where two lowerings overcome the difference of level to the sea. The channel between the locks on the Pacific side is five hundred feet wide at the bottom and forty-five feet deep, and below the Miraflores locks the sea-level section, about eight miles in length, is five hundred feet wide at the bottom and forty-five feet deep at mean tide. Through the lake the bottom widths are not less than one thousand feet for about sixteen miles, eight hundred feet for about four miles, five hundred feet for about three miles and through the continental divide from Bas Obispo to Pedro Miguel, a distance of about nine miles, the bottom width is three hundred feet. The total length of the canal from deep water in the Caribbean, forty-one-foot depth at mean tide to deep water in the Pacific, forty-five-foot depth at mean tide, is practically fifty miles, fifteen miles of which are at sea level.