Gas hydrates are crystalline compounds commonly found beneath Arctic permafrost and in Marine sediments along continental margins. They are thought to play an important role in global climate change, marine hazards, and as an alternative energy source. Reservoir grain size can directly affect the quantity and type of hydrate that is formed. Formation within the sediment is dependent on a number of factors including the interaction between the guest gas molecule and the surrounding water molecules along with the thermodynamic boundary conditions of the system. Once nucleation has occurred the distribution of hydrate is directly related to the pore size of the sediment itself. Hydrate preferentially forms in coarser grained sediment and tends to be pore filling, whereas, hydrate formation within finer-grained sediments results in more complex hydrate distributions such as nodules, lenses, and layers. In this study we examine the grain size of hydrate bearing sediment from marine and Arctic locations and discuss the thermodynamic and nucleation characteristics of gas hydrate in coarse- versus fine-grained sediment.