The National Geodetic Vertical Datum of 1929, an older reference surface that NOAA lists as a synonym for the Sea-level Datum of 1929. NOAA states that NGVD29 is no longer supported by the National Geodetic Survey, and that it should not be read as mean sea level. Older surveys, permits and elevation documents in South Florida often give heights in NGVD29. The difference between an NGVD29 height and an NAVD88 height for the same point is not one fixed number; the relationship between datums varies by location, and NOAA points to its VDatum tool for conversions. If an old document gives your cap height in NGVD29, record it exactly as given and ask a surveyor for the current figure in NAVD88.
Source: NOAA CO-OPS, Datum definitions · Checked 2026-10
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