Several fed banks have gold vaults. For ex the federal bank in new york holds a lot of gold, almost all for other countries, but 1-2% of the gold is held for the us government.
Only one Fed bank has a gold vault, the New York Fed. And as you noted, virtually all the gold is held on behalf of foreign governments and foreign NGOs. The amount of gold held there for the U.S. is also a small fraction of the gold held by the treasury in Denver, Fort Knox, and West Point.