Some intelligence organizations, such as the National Reconnaissance Office and the National Geospatial Intelligence Agency, have declassified most of their organizational charts. The NRO develops, launches and controls spy satellites; the NGA analyzes and distribute imagery. For these agencies, the plumbing matters less than what flows through the pipes, which is highly classified.
But the NSA, with its triple mission -- break codes, secure data, collect signals intelligence -- has not made its structure public. Even by the standards of U.S. intelligence agencies whose existence was declassified much later, the NSA's organization chart is largely impermeable to outsiders. The best of its chroniclers, like Jeff Richelson, James Bamford, Bill Arkin and Matthew Aid, have managed to collect bits and pieces of open source data, but many senior intelligence officials who don't work for NSA still have only a vague idea of what signals intelligence collection entails, and even fewer understand the NSA bureaucracy. The map to the NSA's inner sanctum is generally given only to a select few members of Congress and their staff.
In the interests of transparency and in an effort to establish a basis for continued public exploration of the world of intelligence, I've cobbled together a rough and incomplete but still rather comprehensive organizational chart of the agency's operational, analytical, research and technology directorates.