Geoid heights over the Louisville Ridge seamount chain, deduced from the Seasat satellite altimeter data, have been analyzed and interpreted. Two uncharted seamounts belonging to the chain have been detected. The elastic thickness of the oceanic lithosphere has been determined along the chain. This was done rigorously using the three-dimensional geoid and bathymetry maps and was also computed approximately using spectral methods on geoid and bathymetry profiles. A slightly increasing elastic thickness from the southeast to northwest, in the range 15.5--22.5 km has been estimated.