The right to exploit minerals beneath the ocean floor is highly consequential these days, as it is thought that large deposits of undiscovered petroleum are buried there. The rights to the minerals beneath most of the ocean floor have been allocated to various governments, although some territory remains either unclaimed or in dispute. Any resolution depends on the bases of various claims to sovereignty and ownership with respect to seabed mineral resources.
Most nations with ocean coastline, including the US, extend their territorial claims for twelve nautical miles beyond their shores. The US claims the right to exploit the minerals in this area, to the exclusion of other nations.
State Waters (US)
One consequence of the US federal system is that the various states hold ownership rights to minerals found beneath seabed located within three nautical miles of the state's coastline. Although states exercise the same jurisdiction over these minerals that they do over minerals beneath the states' land area, they are still subject to federal jurisdiction--meaning that in the event of a direct conflict between federal law and state law, federal law almost certainly prevails. That is why it is possible for Congress to ban offshore oil drilling even under state-owned seabed.
Exclusive Economic Zones
Most nations claim an exclusive economic zone extending 200 nautical miles from their coastline, which zone may be contracted as geography dictates (Florida is too close to Cuba, for example, to claim a 200 nautical mile limit). Within this area, nations enforce an exclusive right to exploit minerals buried beneath the seabed. In the US, the national government has exclusive jurisdiction over mineral rights located more than three nautical miles from its coastline and yet still within its exclusive economic zone.
The UN Law of the Sea treaty allows some nations to extend their exclusive economic zone beyond the 200 nautical mile limit under certain geographically defined conditions. A nation may extend its exclusive economic zone up to 350 miles from the baseline from which the outer border of its territorial waters are measured, or up to 200 miles from the nearest point where water depth reaches 2,500 meters, depending on certain geological criteria. The income derived from the exploitation of minerals beyond the 200 nautical mile limit must be shared with other nations through the International Seabed Authority.
In the wake of progressive extensions of national exclusive economic zones, the amount of territory outside of any nation's exclusive economic zone has been steadily shrinking. Mineral deposits in these areas may be treated as available to whoever is willing to extract them, except where formal or informal international arrangements have been made to share these resources.
Leasing to Private Parties
Although ocean mineral rights are almost all owned by governments, these governments are free to lease these mineral rights to others. Some governments lease seabed mineral rights to private parties, and some create their own companies to extract the minerals.