With growing demand for internationally traded biomass, the logistic operations required to economically move biomass from the fi eld or forest to end-users have become increasingly complex. To design cost effective and sustainable feedstock supply chains, it is important to understand the economics, energy and greenhouse gas (GHG) emissions, their interdependencies, and the related uncertainties of the logistic process operations of international supply chains. This paper presents an approach to assessing lignocellulosic feedstock supply systems at the operational level. For this purpose, the Biomass Logistic Model (BLM) has been linked with the Geographic Information Systemsbased Biomass Intermodal Transportation Model (BIT-UU) and extended with inter-continental transport routes. Case studies of herbaceous and woody biomass, produced in the US Midwest and US Southeast, respectively, and shipped to Europe for conversion to Fischer-Tropsch (FT) diesel are included to demonstrate how intermodal transportation and, in particular, overseas shipping integrates with the bioenergy supply chains. For the cases demonstrated, biomass can be supplied at 99 € Mg -1 to 117 € Mg -1 (dry) and converted to FT diesel at 19 € GJ -1 to 24 € GJ -1 depending on the feedstock type and location, intermediate (chips or pellets) and size of the FT diesel production plant. With the fl exibility to change the design of supply chains as well as input variables, many alternative supply chain cases can be assessed.