The North American Vertical Datum (NAVD) is a reference system used to measure elevations across North America. Established in 1978, it provides a consistent baseline for determining the height of land features, such as mountains and valleys, as well as for various engineering and construction projects. NAVD is based on a network of survey benchmarks that have been precisely measured. NAVD replaced the older National Geodetic Vertical Datum (NGVD) of 1929, which had limitations in accuracy. The datum is crucial for floodplain mapping, infrastructure development, and environmental studies, ensuring that data is reliable and comparable across different regions.