The U.S. Department of Housing and Urban Development, otherwise known as HUD, is a U.S. government agency intended to make it easier for Americans to find housing at an affordable rate. Founded in 1965, the agency incorporated the Federal Housing Administration (founded in 1934) as one of it's sub-agencies.
The Government National Mortgage Association, otherwise known as Ginnie Mae, issues mortgage-backed securities, which are "backed by the full credit and faith of the U.S. government." These are based on FHA loans, which include HUD/FHA 221(d)(4) loans, as well as loans issued by the Department of Veterans Affairs (VA).