⚡ FREE · 2,200+ NOAA STATIONS · LIVE DATUMS

Tidal Datums Reference

Search 2,200+ NOAA tide stations for their full tidal datum tables — MHHW, MHW, MSL, MLW, MLLW (chart datum), tidal range and NAVD88 relationship. Essential reference for hydrographic and coastal surveyors. Free.

A tidal datum is a standard elevation defined by a phase of the tide, used as a reference for measuring local water levels and heights. Chart datum (Mean Lower Low Water in the US) is the zero of nautical charts. Hydrographic surveyors reduce soundings to chart datum; coastal engineers relate structures to MHHW or NAVD88. Search any NOAA station below for its official datum table.

60 results · 2,208 stations
8724948EVERGLADES CITY · 25.86, -81.391732417Fare Ute Point · -17.54, -149.579991475Guayaquil · -2.20, -79.878724932Indian Key · 25.80, -81.479455120AGNES COVEAK · 59.77, -149.599456901AGUCHIK ISLAND, KUKAK BAYAK · 58.29, -154.279455145AIALIK BAY, NORTH ENDAK · 59.95, -149.729455146AIALIK SILL, AIALIK BAYAK · 59.88, -149.729458716ANIAKCHAK BAYAK · 56.76, -157.499460150ATTU, MASSACRE BAYAK · 52.84, 173.199461380Adak IslandAK · 51.86, -176.649462719Akun Cove, Akun IslandAK · 54.23, -165.539462694Akutan, AlaskaAK · 54.13, -165.789467645Alakanuk, Yukon RiverAK · 62.69, -164.679457804AlitakAK · 56.90, -154.259451317Anchor PointAK · 56.64, -132.939455606Anchor Point, Cook InletAK · 59.77, -151.879455920AnchorageAK · 61.24, -149.899454794Applegate IslandAK · 60.62, -148.169461710AtkaAK · 52.23, -174.179452534BARTLETT COVE, GLACIER BAYAK · 58.46, -135.889455128BEAR COVE, AIALIK PENINSULA, KENAI PENINAK · 59.80, -149.629450906BECK ISLAND, CLARENCE STRAITAK · 56.05, -132.869465182BLACK ROCK, WALRUS IS BRISTOL BAK · 58.71, -160.199454907BLACKSTONE BAY, PR. WILLIAM SOUNDAK · 60.77, -148.529454381BLIGH ISLAND, T-16AK · 60.81, -146.809454818BLUE FjORD, PORT NELLIE JUANAK · 60.49, -148.249450305BOCA DE QUADRAAK · 55.12, -130.809455777BOULDER POINTAK · 60.78, -151.259451074BUSHY ISLAND, SNOW PASSAGEAK · 56.28, -132.999454755Bainbridge PointAK · 60.20, -148.049451625Baranof, Warm Spring BayAK · 57.09, -134.829452318Barlow CoveAK · 58.32, -134.889494935Barrow OffshoreAK · 71.36, -156.739499176Barter IslandAK · 70.13, -143.619455595Bear Cove, Kachemak BayAK · 59.73, -151.029451287Beecher PassAK · 56.59, -132.999466477Bethel, Kuskokwim River, AKAK · 60.80, -161.759450623Big Salt LakeAK · 55.60, -132.959462645Biorka Village, Biverly InletAK · 53.83, -166.229459251Bird Island, Shumagin BankAK · 54.84, -159.769451281Blaquiere PointAK · 56.58, -132.549450973Blashke IslandAK · 56.13, -132.909451012Bradfield CanalAK · 56.20, -131.569462676Broad BightAK · 54.06, -165.949469677BucklandAK · 65.98, -161.139450914Burrough Bay, Behm CanalAK · 56.04, -131.099454374Busby IslandAK · 60.90, -146.789455151CAMP COVE, HARRIS PENNINSULAAK · 59.69, -149.759451906CANNERY WHARF, GAMBIER BAYAK · 57.48, -133.969464961CAPE CONSTANTINE, NUSHAGAK PENINSULAAK · 58.52, -159.159496345CAPE HALKETTAK · 70.76, -152.349465137CAPE PEIRCE, WEST SIDEAK · 58.63, -161.849454777CHENEGA ISLAND (S.W. END)AK · 60.28, -148.119458917CHIGNIK, ANCHORAGE BAYAK · 56.30, -158.409452421CHILKAT INLETAK · 59.17, -135.409455735CHINULNA POINT, COOK INLETAK · 60.50, -151.289465261CLARKS POINT, NUSHAGAK BAYAK · 58.85, -158.559455558COAL POINTAK · 59.60, -151.419454851COCHRANE BAY, PR. WILLIAM SOUNDAK · 60.66, -148.36

Tidal datum glossary

MHHWMean Higher High WaterThe average of the higher high water height of each tidal day.
MHWMean High WaterThe average of all high water heights.
MTLMean Tide LevelThe arithmetic mean of MHW and MLW.
MSLMean Sea LevelThe arithmetic mean of hourly heights observed over a 19-year (National Tidal Datum) epoch.
MLWMean Low WaterThe average of all low water heights.
MLLWMean Lower Low WaterThe average of the lower low water height of each tidal day — the US chart datum.
GTGreat Diurnal RangeThe difference in height between MHHW and MLLW.
MNMean Range of TideThe difference in height between MHW and MLW.
NAVD88North American Vertical Datum 1988The official orthometric vertical datum for the US, referenced to a fixed benchmark.

Related tools