Natural gas, although predominantly comprised of methane, often contains small amounts of heavier hydrocarbons that contribute to its thermodynamic and transport properties. In this manuscript, we review the current literature and present new correlations for the thermal conductivity of the pure fluids n-octane, n-nonane, and n-decane that are valid over a wide range of fluid states, from the dilute-gas to the dense liquid, and include an enhancement in the critical region. The new correlations represent the thermal conductivity to within the uncertainty of the best experimental data and will be useful for researchers working on thermal conductivity models for natural gas and other hydrocarbon mixtures. (C) 2004 Elsevier B.V. All rights reserved.