Undoubtedly, water is the most abundant and important molecular liquid and is likely the most necessary for life on Earth. The pursuit of understanding water's properties and behaviors has placed it in a unique scientific and even mythical position throughout human history. It is no surprise that much scientific research today centers around this molecule and its interactions with others. The interfacial region between liquid water solutions and other phases is still poorly understood, and only recently have experiments developed to where we can probe this unique environment. Water surfaces exist throughout the Earth's atmosphere and oceans but also make up many of the microscopic interfaces necessary for metabolic processes within living cells. Yet, the influence of water surfaces on the chemistry that drives life and terrestrial processes is still largely unknown, and many research efforts today are attempting to gain insight to this critically important frontier. This dissertation documents several unique computational studies aimed to further our understanding of the complex interactions within a water system and between water and simple, common solutes. Reported herein are the results of molecular dynamics (MD) simulations and computational analysis of interfacial aqueous systems of small hydrated acids, ionic aqueous salt solutions interfaced with a liquid oil, and gas molecules adsorbing onto water surfaces. The composition of the systems chosen for the studies reported in this dissertation reflect environmentally relevant interfaces and also complement recent experimental efforts by the Richmond laboratory. Classical and quantum ab initio MD techniques were used for simulation of the molecular systems and the subsequent analyses provided new information regarding molecular interactions, geometries, orientations, and surface behaviors of water and hydrated interfacial solute molecules. This dissertation includes both previously published and unpublished co-authored material.