A jurisdiction is an area with a set of laws under the control of a system of courts or government entity which are different from neighbouring areas. A jurisdiction is an area with a set of laws under the control of a system of courts or government entity which are different from neighbouring areas. Each state in a federation such as Australia, Germany and the United States forms a separate jurisdiction. However, sometimes certain laws in a federal state are uniform across the constituent states and enforced by a set of federal courts; with a result that the federal state forms a single jurisdiction for that purpose. It is also possible for a jurisdiction to prosecute for crimes committed somewhere outside its jurisdiction, once the perpetrator returns. In some cases, a citizen of another jurisdiction outside its own can be extradited to a jurisdiction where the crime is illegal, even if it was not committed in that jurisdiction. Unitary states are usually single jurisdictions, but the United Kingdom is a notable exception; it has three separate jurisdictions due to its three separate legal systems. China also has separate jurisdictions of Hong Kong and Macao.