Regulations and public opposition can make siting municipal solid waste landfills difficult. In this paper, spatial-AHP is presented, a method that identifies and ranks potential landfill areas for preliminary site assessment. Spatial-AHP takes into account regulatory restrictions, area attributes, and site assessment criteria provided by experts and/or users. The method uses an analytic environment provided by geographic information systems (GIS) and a decision-making method provided by the analytic hierarchy process (AHP). The GIS is used to manipulate and present spatial data. The AHP is used to rank potential landfill areas based on a wide variety of criteria. Spatial-AHP is demonstrated by applying it to a landfill site selection study in Cleveland County, Oklahoma. The paper also analyzes the effects of varying the relative importance of various siting criteria, landfill size, and location restriction severity.