Open single-wall carbon nanohorns (SWNHs) were compressed repeatedly at 50 MPa to generate a nanocarbon material of high bulk density. TEM observations and Raman spectroscopy revealed a significant distortion in the structure of the compressed SWNHs. The obtained nanostructured disordered carbon exhibits a high methane storage capacity, reaching 160 cm(3)/cm(3) of nanocarbon at 3.5 MPa and 303 K. Comparison of the experimental results with grand canonical Monte Carlo simulations indicates the importance of the adsorption in the interstitial channels for the high total adsorption capacity of the generated nanostructured carbon.