High-resolution multichannel seismic reflection data, exploration industry 3D seismic data, and heat flow measurements collected on the southeast side of a minibasin (Casey basin) in the northern Gulf of Mexico continental slope have been used to characterize a bottom simulating reflection (BSR). The BSR, which covers a small area of about 15 km2, is identified by cross cutting relationships with seismic stratigraphy. Two mounds are identified; the larger Alpha mound is structurally formed at the junction of three arms of the structural high east of the minibasin. The smaller Beta mound may be a seep site. Conventional heat flow measurements yield higher gradients (39-49 mK/m) to the northeast of the structural high and lower values (30-38 mK/m) to the south and west along the edge of the minibasin, which is separated from the structural high by the eastern Casey fault zone. When the near-seafloor thermal gradients are extrapolated to the depth of the BSR, the resulting temperatures are generally too low if the BSR marks the base of the hydrate stability zone in a methane-only gas hydrate system. Plausible changes in pore water salinity or gas composition cannot account for this disparity, and thermal perturbations caused by fluid downwelling, mass wasting, or depth-dependent thermal conductivity variations might best explain the low predicted BSR temperatures. The recognition of a BSR in the study area provides geophysical evidence that a hydrate stability zone with trapped free gas at its base exists in the northern Gulf and that minibasins can be locations for finding subsurface hydrate-associated free gas and probable gas hydrate.