Unless otherwise noted, the terms identified below were excerpted from Reed, Michael W. (NOAA/DOC GPO 2000) Shore and Sea Boundaries: Volume Three. This volume is out of print but may be downloaded. The links in brackets indicate the page(s) at which the term is referenced. LOSC is the Law of the Sea Convention. The 1958 Convention is the 1958 Convention on the Territorial Sea and the Contiguous Zone.
The U.S. Extended Continental Shelf Project also provides a Glossary of Terms and Abbreviations related to their mission.
Ambulatory. Not stationary. Baselines from which maritime boundaries are measured ambulate with accretion and erosion causing ambulation of the boundaries themselves.
Archipelagic waters are the waters enclosed by the archipelagic baselines drawn in accordance with LOSC Article 47 offsite link. The archipelagic state has full sovereignty over these waters, but foreign vessels have the right of innocent passage through archipelagic waters (like they do through territorial seas) subject to LOSC. Article 53 offsite link. [Zones and Boundaries]
Artificial Islands. Offshore structures or features that do not meet the LOS Convention's definition of "island" in that they were not "naturally formed." Mineral production platforms and spoil banks are examples. Artificial islands are not part of the baseline from which maritime zones are measured.
Bay. An indentation of water into land that meets the requirements of Article 7 of the 1958 Convention on the Territorial Sea and the Contiguous Zone and Article 10 of the LOSC. An inland water body.
Breakwater. A man-made structure extending seaward from the natural coastline which has an apparently continuous low-water line. Often constructed to affect the movement of water. A harborwork. Part of the coast line from which maritime zones are measured. Often contrasted with piers.
Cannon Shot Rule. Said to be the original criterion for establishing the breadth of the marginal sea. Advanced by Cornelius Van Bynkershoek in 1702 when cannon were said to have a range of approximately three miles.
Closing Line. The line dividing inland waters and the territorial sea at the mouth of a river, bay, or harbor.
Coast Guard Line. Lines constructed by the United States Coast Guard to separate areas of the sea where the Inland Rules of the Road apply from those where the International Rules are in effect. Found by the Supreme Court to have no bearing on the location of the coast line or inland waters as those terms are used in the LOSC and the 1958 Convention.
Coast Line. The term used in the Submerged Lands Act to describe the low-water line and closing lines across the mouths of inland water bodies. The same as "baseline" in the LOSC and the 1958 Convention.
Coast Protective Works. Man-made structures erected along the coast, such as jetties and groins. Harborworks. Treated as part of the coast line for purposes of maritime zone delimitation.
Coastline. The water/land interface. The shoreline. A more general term than "coast line."
Double-Headed Bay. A pair of adjacent bays that share a central headland. If, when considered together, the two indentations meet the requirements of Article 7 of the 1958 Convention and LOSC Article 10, they may be combined to form a single juridical bay with a closing line joining their non-common headlands.
Dredged Channel. An artificially maintained sea lane extending from an inland water body into the marginal sea to accommodate vessel traffic through coastal shallows. Louisiana contended that such submerged features are "harborworks" and part of the coast line. The Supreme Court held otherwise.
English Seas. A maritime belt of sovereignty asserted around the British Isles by Charles I (1625-1649). Also called the "narrow seas."
Entrance Points. The points on the low-water line that are joined to create a closing line marking the seaward limits of inland waters.
Equidistant Line. A line that is at all times equidistant from two adjacent or opposite coast lines. It is, in the absence of special circumstances, the preferred method for constructing lateral offshore boundaries. Used to continue the common boundary between Texas and Louisiana (in the Sabine River) to the limit of their Submerged Lands Act grants. Also known as a "median line."
Fallback Line. A line of 24 miles length constructed within an overlarge bay to define the limit of inland waters. Article 7 of the 1958 Convention and LOSC Article 10 provide that the inland waters of a bay will extend to a line between its natural entrance points only if those points are 24 miles or less apart. The inland waters of a bay that meets all of the legal requirements of Article 7 except for the 24-mile maximum mouth extend seaward to an arbitrary line of 24 miles constructed within the bay such that the maximum water area is enclosed. 1958 Convention Article 7 and LOSC Article 10.
Fictitious Bay. A water area enclosed by the mainland and offshore islands. Some pre-LOS Convention proposals would have treated such areas as inland waters. Others would have treated them as territorial sea, even though farther from land than the claimed breadth of the territorial sea. Under the LOS Convention such areas are territorial seas and high seas unless enclosed by Article 4 straight baselines. 1958 Convention Article 7 and LOSC Article 10.
Forty-five Degree Test. The preferred method of locating the proper headlands and entrance points for an inland water body. The test determines whether the coastline between two potential entrance points faces more on the inland water body or the open sea. If the former, the more seaward potential headland is employed; if the latter, it is rejected and the more landward option is similarly evaluated.
Geographic Mile. A unit of linear measure equal to one minute of latitude at the equator. 6080.2 feet. Also known as a nautical mile. Unless otherwise noted, references to a "mile" in this work are to the geographic or nautical mile.
Groin. An artificial structure, like a small jetty, extending from the shore. Usually for the purpose of preventing beach erosion. Treated as a harborwork. Part of the coast line from which Submerged Lands Act grants and zones of maritime jurisdiction are measured.
Harbor. A place where ships may find shelter. A harbor may be natural or artificially constructed. In either case its waters are inland. The limits of its inland waters are determined, at least in part, by their use as a harbor rather than the mere application of delimitation principles to geography, as is the case with bays and rivers.
Harborwork. Artificial structures erected to protect the coast or provide shelter. Treated as part of the coast line pursuant to Article 8 of the 1958 Convention and LOSC Article 11.
Headland A geographic feature that serves to give an inland water body its landlocked nature. A headland may be natural or man-made. It must be above mean low water but not by any significant extent. It will usually provide an appreciable change in the direction of the coast.
High-Seas Enclave. An area of high seas entirely surrounded by territorial seas generated by the mainland and islands that lie more than twice the breadth of the territorial sea offshore.
Historic Bay. A water area over which the coastal state has asserted sovereignty, over a long period of time, with the acquiescence of foreign nations. The geographic requirements for a juridical bay, as set out in Article 7 of the 1958 Convention and LOSC Article 10, need not be met.
Historic Boundary. As used in this volume, a state's boundary at the time it entered the Union. Congress, through the Submerged Lands Act, permitted states bordering on the Gulf of Mexico to prove historic boundaries of up to 3 marine leagues (9 nautical miles) offshore. Their Submerged Lands Act grants would then extend to the lesser of those lines or lines 3 leagues from the present coast line. Florida and Texas provided such proof and received the extraordinary grant. Louisiana, Mississippi, and Alabama could not.
Historic Inland Waters. Water areas over which inland water jurisdiction has been asserted for a substantial period of time with the acquiescence of foreign states. See: Historic Bay.
Historic Territorial Seas. Water areas over which territorial sea jurisdiction has been asserted for a substantial period of time with the acquiescence of foreign states.
Inland Water Line A series of straight lines developed by the Coast Guard to separate areas that are subject to its Inland Rules of the Road from those to which the International Rules apply. The lines have no bearing on inland water determinations for LOS Convention or Submerged Lands Act purposes. See: Coast Guard Line.
Inland Waters Waters landward of the baseline from which the marginal seas are measured and over which complete sovereignty is exercised. Also known as "internal waters."
Innocent Passage The right of a vessel to navigate through the territorial sea of a foreign state for purposes of traveling from one area of high seas to another or passing between the high seas and the inland waters of the coastal state.
In situ preservation is a precautionary management approach in which the first option for protection and management is to leave the site as it was found. It is a current professional practice for managing heritage resources in place when the disruption of the site could lead to its destruction. It is not intended to create any legal presumption to preclude recovery or salvage. To the contrary, the Annex Rules set forth the requirements for recording information about the site and the context of any artifacts before and during the recovery or salvage of such artifacts because otherwise the contextual information would be lost forever. See also, Comment 11 of the Titanic Guidelines, 66 Fed. Reg. 18906 (April 12, 2001). [International Agreement]
Jetty. A substantial, artificial structure erected on the coast for the purpose of extending the flow of a river or protecting a harbor or beach. A harborwork. Part of the coast line for LOS Convention and Submerged Lands Act purposes. See: Breakwater.
Juridical Bay. An indentation into the mainland that qualifies for inland water status under the criteria of Article 7 of the 1958 Convention and LOSC Article 10. Because these provisions are self-executing, a coastal state need not put foreign nations on notice of the inland water status of juridical bays. 1958 Convention Article 7 and LOSC Article 10.
King's Chambers. Coastal waters within lines between distant headlands that "squared off" the British Isles. Proclaimed by James I in 1604, the waters constituted a neutral zone within which foreign warships were prohibited from engaging in combat. The Chambers have no continuing significance.
Landlocked. Separated from the open sea by mainland headlands. For practical purposes, any indentation into the mainland that meets the requirements of Article 7 of the 1958 Convention and LOSC Article 10.
Lateral Offshore Boundary. The offshore extension of land boundaries between adjacent coastal states to the limits of their offshore jurisdiction. In the absence of agreement such boundaries are described as a median or equidistant line. 1958 Convention, Article 12 and Article 15. The Texas/Louisiana, South Carolina/Georgia, and Maine/New Hampshire lateral boundaries have been litigated and are discussed in this volume.
Law of the Sea LOS Convention. The United Nations' 1982 LOS Convention that, for most purposes, supercedes the four Geneva LOS Conventions of 1958. The "baseline" provisions of the Law of the Sea LOS Convention do not deviate significantly from those of the LOS Convention on the Territorial Sea and the Contiguous Zone. The Supreme Court's adoption of the 1958 principles for purposes of the Submerged Lands Act is not affected by the new LOS Convention. Entered into force on November 16, 1994. The United States has recognized most provisions of the 1982 LOS Convention as customary international law (including the baseline provisions) but, at the time of this writing, has not ratified the LOS Convention.
Limits of the Tides Test. A proposal that river waters, running upstream to the limit of tidal effect, should be included within the area of the water body into which they flow for purposes of determining whether that body qualifies as inland water (that is, meets the semicircle test of Article 7 of the 1958 Convention and LOSC Article 10).
Littoral Bordering on the sea.
Low-Tide Elevation. A naturally formed area of land that is surrounded by and above water at low tide but below water at high tide. Low-tide elevations serve as part of the coast line when they are within the breadth of the territorial sea of the mainland (either uplands or inland waters) or an island. 1958 Convention, Article 11 and LOSC Article 13. 388 Shore and Sea Boundaries.
Marginal Sea. The maritime belt over which a coastal state asserts sovereignty. See: Territorial Sea.
Marine League. Three nautical, or geographic, miles.
Median Line. See: Equidistant Line.
Mixed Tides. Two high and two low tides per day. Typical of the Pacific coast of the United States.
Mouth. Entrance to an inland water body. The line that divides inland waters from the territorial sea.
Narrow Seas. See: English Seas.
Natural Entrance Points. Points on the headlands of an inland water body that serve as the termini of its closing line.
Naturally Formed. Composed of natural substance which has been naturally placed. One of the requirements for island and low-tide elevation status under Articles 10 of the 1958 Convention and LOSC Article 121, and Article 11 of the 1958 Convention and LOSC Article 13.
Nautical Mile. See: Geographic Mile.
Navigable Waters. Waters that are either tidally influenced or navigable in fact.
Normal Baseline. The low-water line as adopted for large-scale charts by the official government charting agency.
OCSLA. The Outer Continental Shelf Lands Act. 43 U.S.C. 1331 et seq. Federal legislation which, for the first time, provided a mechanism for the administration of mineral resources seaward of the territorial sea. Enacted shortly after passage of the Submerged Lands Act in 1953. Appendix A 389
Overlarge Bay. An indentation into the mainland that meets all requirements of Article 7 of the 1958 Convention and LOSC Article 10 for inland water status except that its entrance is more than 24 miles across. Cook Inlet, Alaska, is an example. Article 7 of the 1958 Convention and LOSC Article 10 provide that in such circumstances a "fallback line" of 24 miles shall be drawn within the indentation to enclose the maximum possible water area.
Paramount Rights. The term used by the Supreme Court to describe the federal interest in offshore submerged lands prior to passage of the Submerged Lands Act.
Pier. An artificial structure erected on the coast and extending into the sea. Distinguished from jetties and breakwaters in that its platform is generally supported by pilings that do not produce a continuous low-water line and are not intended to affect the movement of water or provide a coast protective function.
Port. A protected place along the coast in which ships may take refuge from storms or transfer cargo. A harbor. Protection may be provided by natural or artificial features. The waters of a port are inland.
Quitclaim. A release or relinquishment of all of the grantor's interest without a warranty of title.
Roadstead is an area of the sea used for the anchorage of vessels and transhipment of cargo, usually without the protection from weather associated with ports and harbors. Roadsteds are part of the territorial sea and not inland waters. [Zones and Boundaries]
Self-Executing. Occurring by operation of law. Needing no further act for implementation.
Semicircle Test. The requirement of Article 7 of the 1958 Convention and LOSC Article 10 that to qualify as a juridical bay an indentation in the coast must, at a minimum, contain a water area equivalent to that of a semicircle whose diameter is that of the indentation's mouth.
Shortest Distance Test. The method for locating the entrance point of an inland water body when only one distinct headland exists. In such cases the shortest possible line is drawn from that headland to the opposite coast.
Spoil Bank. An artificial formation created by the deposit of dredged materials on the seabed. Spoil banks that are connected to the natural coastline are part of the baseline from which maritime zones are measured. Those that are unattached are artificial islands and are not part of the baseline.
Statute Mile. 5280 feet. Also known as a "land mile" or "English mile."
Straight Baselines. An artificial coast line from which maritime zones are measured. Appropriate for coastlines that are deeply indented or masked by a fringe of islands. Article 4 of the 1958 Convention and LOSC Article 7 provide the rules for straight baselines. The United States has never adopted such baselines.
Submerged Lands Act. Federal legislation that granted to the coastal states federal rights to natural resources within 3 nautical miles (up to 9 miles for Texas and the Gulf coast of Florida) of the coast line. 43 U.S.C. 1301 et seq.
Subsidiary Water Body. A river that empties into, or bay that opens onto, another water body. Numerous questions have arisen in the tidelands litigation as to whether or when the area of subsidiary water bodies may be included for purposes of applying the semicircle test to a primary indentation under consideration for inland water status.
Three-League Boundary. The historic offshore boundaries of Texas and of Florida in the Gulf of Mexico. The seawardmost extent of Texas's and Florida's Submerged Lands Act grant in the Gulf.
Tidelands. The zone between the mean high-water line and the mean low-water line, commonly referred to as the "beach." Waters above the tidelands are inland, being landward of the coast line. Despite the traditional reference to "tidelands litigation," the United States never questioned state jurisdiction over these lands. The "tidelands cases" involved only submerged lands seaward of the low-water line.
Tidelands Cases. That body of litigation between the federal government and the coastal states that has determined ownership over submerged lands and resources seaward of the coast line and defined that coast line through the application of international law.
Truman Proclamation. A proclamation through which the United States unilaterally claimed exclusive jurisdiction over the resources of its continental shelf beyond the marginal sea. Presidential Proclamation No. 2667 of September 28, 1945, 59 Stat. 884.
Well-Marked Indentation. An indentation of water into the mainland that is more than a mere curvature of the coast. The first requirement for juridical bay status under Article 7 of the 1958 Convention and LOSC Article 10.