The specialisation may be imposed voluntarily by policy, consensus with other agencies, or logistical constraints, or it could be imposed legally by law and jurisdiction, or it is result of the historical evolution of the agency, or combinations thereof.
For example, some agencies only enforce laws related to taxation or customs.
Other agencies can only operate in certain areas, for example government-occupied buildings and land, or on waterways.
Some agencies have otherwise unrestricted jurisdiction, but specialise in certain types of operations, for example highway patrols.
Specialities can include: See Specialist law enforcement agencies for a list of specialist agencies.