One of the best alternative and renewable hydrocarbon sources is plant biomass, which can be converted into transportation fuels and chemicals. Advantages of utilizing plant biomass as an energy source include its availability within the U.S. and its post-conversion potential to be incorporated into the current liquid transportation fuel infrastructure. Preliminary experiments with lignin-based feedstocks and high temperature water (350-400°C) are explored in an effort to observe the fundamental reactions and to optimize the characterization methods used for each type of phase generated. The use of different catalysts and/or gas atmospheres is also investigated as a means to improve lignin conversion at near supercritical conditions. Understanding the chemistry of lignin conversion has been challenging, yet this dictates how the by-products formed might be implemented into various existing processing facilities.