An exclusive economic zone, or EEZ, is a sea area beyond and next to a country’s territorial sea where the coastal state has special rights to explore, use, conserve and manage natural resources. It can extend no farther than 200 nautical miles from the coastal baseline. Other states retain important freedoms, including navigation and overflight.
NOAA’s U.S. EEZ overview describes jurisdiction over resources in the water, seabed and subsoil, plus activities such as energy production. An EEZ is therefore neither ordinary high seas nor the same as sovereign land territory. It is a distinct legal zone balancing coastal-state resource rights with international use of the ocean.
Where the 200 miles begin
The distance is measured from a legal baseline, usually the low-water line shown on officially recognized coastal charts. A nautical mile equals 1,852 meters, so 200 nautical miles equal 370.4 kilometers or about 230 statute miles. The EEZ lies outside the territorial sea, which generally extends to 12 nautical miles from the same baseline.
Coasts are irregular, islands may generate their own zones and neighboring countries can lie less than 400 nautical miles apart. In those cases, claimed zones overlap and the states must delimit a boundary under international law, often through agreement. A map that draws a simple 200-mile buffer can therefore exaggerate the zone near another country.
The United Nations Convention on the Law of the Sea states in Article 57 that an EEZ shall not extend beyond 200 nautical miles from the territorial-sea baselines. The distance is a maximum entitlement, not a promise that every coastal state controls a complete 200-mile ring.
Islands can affect the calculation, but UNCLOS distinguishes islands from rocks that cannot sustain human habitation or an economic life of their own. Under Article 121, such rocks have no EEZ or continental shelf. Low-tide elevations follow another set of rules in the convention. Whether a feature qualifies can carry enormous consequences because a small speck of land may otherwise influence rights across a broad sea area.
Rights held by the coastal state
Within its EEZ, a coastal state has sovereign rights for exploring, exploiting, conserving and managing living resources such as fish. The same principle covers nonliving resources of the seabed and subsoil, including oil, gas and minerals. “Sovereign rights” are purpose-specific rights, a narrower concept than full sovereignty.
The state also has jurisdiction specified by the convention over artificial islands and installations, marine scientific research and protection of the marine environment. It can regulate fisheries and authorize offshore energy projects. The state also sets conditions for certain research. These powers come with duties, including conservation obligations and due regard for other states’ lawful rights.
Energy from water, currents and winds is named among economic uses of the zone. Offshore wind leasing, however, involves domestic agencies and additional laws beyond the international definition. An EEZ supplies the jurisdictional setting; it does not itself grant a company permission to construct a turbine or drill a well.
Resource rights are paired with management obligations. For fisheries, the coastal state determines the allowable catch using the best scientific evidence available and must act to prevent stocks from being endangered by overexploitation. Stocks that cross boundaries require cooperation because a fish does not stop at the charted limit. The legal zone allocates authority, while conservation still depends on monitoring and enforcement.
Freedoms retained by other states
Foreign merchant ships do not generally need the coastal state’s permission simply to navigate through an EEZ. All states retain freedoms of navigation and overflight, along with laying submarine cables and pipelines, subject to the convention and due regard for the coastal state’s rights. The EEZ cannot be treated as a closed national lake.
Fishing is different because the coastal state controls the living resources of its EEZ. Foreign vessels need authorization where national rules require it and illegal fishing may bring enforcement action. Scientific research can also require consent because the coastal state has jurisdiction over marine scientific research under the convention.
Military activities are a source of legal and diplomatic disagreement in some regions. Broad EEZ rules establish shared rights and duties, but states do not always interpret every activity identically. Specific disputes can involve treaties, customary international law, national positions and facts about the operation.
The convention applies a due regard standard in both directions. Coastal states must consider the rights of other states when exercising their EEZ powers and other users must consider the coastal state’s rights. Early notice and consultation can reduce interference before an operation begins, as can careful route planning. Practical conflicts over a cable route, fishing operation, or survey cannot be resolved by treating either side’s interest as automatically absolute.
EEZ, territorial sea and continental shelf
The territorial sea extends up to 12 nautical miles from the baseline. The coastal state exercises sovereignty there, subject to rules such as innocent passage for foreign ships. The contiguous zone can extend to 24 nautical miles, allowing limited enforcement related to customs, immigration, fiscal and sanitary laws.
The continental shelf is a legal regime focused on seabed and subsoil resources. A coastal state may have shelf rights beyond 200 nautical miles where the continental margin meets detailed criteria, although water-column rights beyond the EEZ do not automatically follow. The legal shelf also exists even when the seabed is geologically different from what everyday language calls a shelf.
NOAA’s maritime boundaries portal depicts U.S. territorial-sea, contiguous-zone and EEZ limits on nautical products. The lines are operationally important for resource management, charting, enforcement and cross-border coordination.
A legal continental shelf also differs in how rights arise. Coastal-state rights over the shelf exist without occupation or an express proclamation and concern the seabed and subsoil. An EEZ, by contrast, adds rights in the overlying water column. Beyond 200 nautical miles, a qualifying extended shelf does not create an extended fishing zone above it.
The U.S. EEZ in practice
The United States proclaimed a 200-nautical-mile EEZ in 1983. It includes waters associated with the states and territories, so its geography stretches across the Atlantic, Pacific, Arctic, Gulf and Caribbean. Island territories account for a substantial share of the area.
The United States has signed but has not ratified the 1982 Law of the Sea Convention. It recognizes many convention provisions, including the EEZ framework, as reflecting customary international law. NOAA explains that federal agencies use the framework and maintain the maritime limits shown on official charts.
Management is divided among agencies according to activity. NOAA Fisheries manages many living marine resources and conducts enforcement with partners. Offshore energy and mineral programs involve other federal bodies. The Coast Guard performs maritime law-enforcement and safety missions, while the State Department handles international boundary diplomacy.
Enforcement power follows the subject at issue. A fisheries patrol may inspect permits and catch, while an offshore-energy regulator reviews lease conditions and environmental requirements. A foreign ship that is merely navigating exercises a different right. Identifying the activity comes before identifying the responsible agency, a distinction that helps explain why no single office “controls” every use of the U.S. EEZ.
Readers checking a specific location should use official coordinates rather than estimating from the beach. Baselines can change with accretion or erosion and negotiated boundaries interrupt the maximum-distance arc. NOAA’s law-of-the-sea summary explains how charted baselines support U.S. maritime limits. The durable idea is simple: an EEZ gives the coast special economic and environmental jurisdiction while preserving major international freedoms.
Related reading: marine protected areas and reserves and ocean and sea terminology.
