WASHINGTON — In passing references scattered through once-classified documents and cryptic public comments by former intelligence officials, it is referred to as “Midwest Depot,” but the bland code name belies the role it has played in some of the C.I.A.’s most storied operations.

From the facility, located somewhere in the United States, the C.I.A. has stockpiled and distributed untraceable weapons linked to preparations for the Bay of Pigs invasion and the arming of rebels and resistance fighters from Angola to Nicaragua to Afghanistan.

Yet despite hints that “Midwest” was not actually where it was located, the secrecy surrounding the C.I.A. armory has survived generations of investigations. In a 2007 essay on the 20th anniversary of the Iran-contra affair, for example, a congressional investigator noted that the facility where the C.I.A. had handled missiles bound for Iran remained classified even as other “incredible things were unveiled during the hearings.”

But three years ago, it became public that the C.I.A. had some kind of secret location at Camp Stanley, an Army weapons depot just north of San Antonio and the former Kelly Air Force Base, though its purpose was unclear. And now, a retired C.I.A. analyst, Allen Thomson, has assembled a mosaic of documentation suggesting that it is most likely the home of Midwest Depot.