A methodology for estimation of seafloor topography has been implemented using a hydrodynamics-based inverse model in which the bottom topography is regarded as a control variable. When applied to the Sea of Okhotsk, a region of sparse in situ bathymetry, a new map of the seafloor is obtained which is constrained by hydrodynamics and which agrees with altimeter-derived observations of tides. While validation of the new seafloor map requires additional in situ data, the topography is expected to be an improvement upon previous gravimetrically-derived topography, particularly over the continental shelf where the relationship between topography and gravity is uncertain. The significant influences of model resolution, bottom drag parameterization, and the hypothesized topography error spatial covariance will be discussed.