Recently, theories for ocean dynamics posit that submesoscale flows interacting with near-inertial motions are important for understanding the dynamics of both phenomena. These data provide a basis to test theories of energy exchange at the submesoscale by studying circulation patterns in the Mississippi-Atchafalaya river plume in the northern Gulf of Mexico. Observations from ship, moorings, and autonomous platforms made during two field campaigns are complemented by hydrostatic ROMS modeling and non-hydrostatic Large Eddy Simulations (LES). By combining data and models, we characterize, quantify, and understand the energy exchanges between balanced and unbalanced motions and the turbulent cascade that can result from the interaction. Wave-mean flow interactions in the Mississippi-Atchafalaya river plume system could enhance mixing and vertical exchange, which are important for understanding coastal hypoxia and the dispersal of pollutants in the northern Gulf of Mexico. The data archived here are field observations from multiple ships that capture circulation patterns, stratification variability and turbulence intensity in the Mississippi-Atchafalaya River plume in the northern Gulf of Mexico. The region is characterized by a strong sea breeze which leads to the flow and wave variations on relatively small spatial scales of less than 1 km. Observations were obtained during two intensive field campaigns that included ship, moored, and autonomous platforms. The project is a collaboration between the US and the United Kingdom (UK) with the UK component being supported by the UK National Environmental Research Council (NERC) through an agreement with NSF.