This paper describes a technique to estimate, from measured surface clutter, parameters defining a surface-based duct using a simple ray trace method. The approach is novel in that it incorporates a rank correlation scheme between the observed surface clutter and the surface ray density for a given propagation path. While more sophisticated methods for duct parameter estimation have been developed with successful results, these have concentrated on using observations entirely from sea surface clutter. The technique described here looks at using land clutter also as an added source of information to adequately estimate surface-based duct parameters.