According to Epcot Guest Relations, the original geographic center point of Walt Disney World is just south of the Fountain of Nations in Epcot's Future World. If you look on the ground on the plaza behind the fountain, as you walk toward World Showcase, you'll see the original Epcot logo embedded in the pavement. It consists of five intertwined circles around a globe. The 'globe' marks the original geographic center of the property. The reason I say 'original geographic center' is that since 1982, when Epcot opened, the boundaries of the WDW property have changed several times. The logo isn't the center anymore, although it is probably fairly close.