Lithotypes (vitrain, clarain, and fusain) of high volatile bituminous Pennsylvanian coals (Ro of 0.56−0.62%) from Indiana (the Illinois Basin) have been studied with regard to meso- and micropore characteristics using low-pressure nitrogen and carbon dioxide adsorption techniques, respectively. High-pressure CO2 adsorption isotherms were obtained from lithotypes of the Lower Block Coal Member (the Brazil Formation) and the Springfield Coal Member (the Petersburg Formation), and after evacuation of CO2, the lithotypes were re-analyzed for meso- and micropore characteristics to investigate changes related to high-pressure CO2 adsorption. Coal lithotypes have differing Brunauer−Emmett−Teller (BET) surface areas and mesopore volumes, with significantly lower values in fusains than in vitrains or clarains. Fusains have very limited pore volume in the pore size width of 4−10 nm, and the volume increases with an increase in pore size, in contrast to vitrain, for which a 4−10 nm range is the dominant pore width. ...