Mean High Water (MHW) is a Tidal Datum representing the average of all the daily tidal high water heights observed over a period of several years. In the United States this period spans 19 years and is referred to as the National Tidal Datum Epoch. The most current MHW values are found in the North American Vertical Datum of 1988 (NAVD 88).
- Chart datum – The level of water from which depths displayed on a nautical chart are measured
- "Tidal Datums". tidesandcurrents.noaa.gov.