This dataset is based on archives from the University of Miami’s high-resolution (1/50 degrees, 1.8km) configuration of the Hybrid Coordinate Ocean Model (HYCOM) in the Gulf of Mexico (GoM-HYCOM 1/50) for the year of 2015. The GoM-HYCOM 1/50 used realistic river forcing parameterization with daily river discharge obtained from the Army Corps of Engineers and the U.S. Geological Survey (USGS). Atmospheric forcing was from the European Center for Medium-Range Weather Forecasts (ECMWF) at 0.125-degree spatial resolution and it is nested within a Global HYCOM. The model assimilated satellite observations of sea surface temperature and sea surface height and in situ observations of temperature and salinity. The GOM-HYCOM 1/50 gives details on the fronts and filaments associated with the Mississippi River plume dynamics, as well as GoM mesoscale processes. The dataset includes the surface model fields of temperature, salinity, currents and sea surface height from the GoM-HYCOM 1/50 at 12Z along with two experimental simulations designed to study the effect of river front; Reference, noMR (without Mississippi River), and noMR_noPcip (without Mississippi River and precipitation).