The term submerged lands is primarily used in the United States to describe lands lying below the high tide line or high water mark.1 The accompanying figure depicts the terms used by different countries, sources, and states to describe lands lying below the high tide line.
A Complex Term in the U.S.
The term submerged lands is complex and often confusing as there is little standardized application of submerged lands in the U.S. For example, a major federal law (the Submerged Lands Act) and a renowned publication (Putting the Public Trust Doctrine to Work, Sade et al., 1997) are inconsistent in their use of the term as are many individual states.
U.S. State Submerged Lands
In general, U.S. state submerged lands (along ocean coasts) are considered those lands lying between the high or low tide line of a state and the seaward jurisdictional limit of the state, which is normally three nautical miles (except for Texas, Florida, and Puerto Rico within the Gulf of Mexico where the seaward jurisdictional limit is nine nautical miles).
Several issues complicate the use of the term submerged lands:
- States do not always use the term submerged lands. Instead, states use various and often inconsistent terms, such as aquatic lands, tidelands, water bottoms, and underwater lands (among other terms), to describe areas below the high tide line.
- States often, but not always, use different terms to describe subsets of areas that lie below the high tide line. States may refer to areas close to shore differently than areas further offshore. States may also refer to areas within estuaries and bays differently than areas along the open coast.
- Many states use different terms and measurements to describe the landward extent of submerged lands, such as the wash up line, extreme high tide line, or mean high water mark (and several different combinations and variations of the aforementioned terms).
- Some states are considered high-water states2 and others are considered low-water states3. In high-water states, the submerged lands are typically thought to extend landward to a state-defined high water line while in low-water states the submerged lands are typically thought to extend landward only to a state-defined low water line. This does not mean, however, that state ownership always or only extends to the high or low water line (further discussion on this can be found within Public Ownership).
U.S. Federal Submerged Lands
U.S. Federal submerged lands are considered those lands starting at the seaward extent of states' jurisdictional limits and extending further seaward to the extent of the U.S. Federal Exclusive Economic Zone (200 nautical miles).
Sub tidal and Inter tidal Lands
The terms inter tidal lands and sub tidal lands are used somewhat consistently throughout the United States. These terms are more descriptive and functional, as opposed to legal, in nature when compared to submerged lands. In general, inter tidal lands are considered those lands lying between the high tide and low tide while sub tidal lands are considered those lands lying below the low tide.
1 Since the focus of this toolkit is on ocean and related coastal conservation, further discussion on submerged, inter tidal, and sub tidal lands will be limited to application of the terms to saltwater areas.
2 High-water states include: Alabama, Alaska, California, Connecticut, Florida, Georgia, Hawaii, Louisiana, Maryland, Mississippi, New Jersey, New York, North Carolina, Oregon, Rhode Island, South Carolina, Texas, and Washington State.
3 Low-water states include: Delaware, Massachusetts, Maine, New Hampshire, and Virginia.