HG is a huge legal portal with comprehensive US listings. The UK section is limited, but there are international links to 230 countries - this includes a link to every government in the world. The 'areas of practice' guides are very useful: each entry (e.g. Aboriginal Peoples) will be broken down into Supranational Organisations, National Regimes. United States Info, Publications and Associations.
The link below will open the external site in a new window: