An evaluation of the Regional Mercury Cycling Model (R-MCM, a steady-state fate and transport model used to simulate mercury concentrations in lakes) is presented based on its application to a series of 91 lakes in Vermont and New Hampshire. Visual and statistical analyses are presented in an effort to investigate both the behavior of the model as well as the model's ability to predict the observed mercury concentrations in the water column, sediments and fish tissue. The sensitivity of the model to certain parameters and processes was also evaluated. A comparison of model trends to the observed trends was made. These investigations provide further insight into the complications and challenges that surround modeling the fate and transport of mercury within a given water body, and understanding the exposure concentrations of mercury in the surrounding ecosystem via mercury bioaccumulation in the aquatic food web (e.g., fish) and its transfer to piscivorous wildlife and humans.