Using a sample of 1,651 US households, we explore some determinants of willingness to pay (WTP) for climate change mitigation programs. Our mail survey had a relatively low response rate, so we first use several additional data sources to build a detailed sample selection model. This model uses features of the survey instrument, measures of geographic vulnerability to climate change, seasonality, the political mix in the county, attributes of the address or addressee, and a set of factor scores from an extensive factor analysis of all census tracts in the US. We estimate this model jointly with a model to explain climate policy preferences as a function of the domestic and international distribution of policy costs as well as the climate change impacts that each respondent believes will occur under a policy of business-as-usual. Despite statistically significant patterns of nonresponse, selectivity effects are minimal in this case. WTP for climate change mitigation is greater when the domestic incidence of mitigation costs is borne mostly through higher energy taxes. It is also greater when costs are understood to be shared internationally with other groups of countries, rather than being borne mostly by a country group including the US. People are generally more willing to pay for climate change mitigation if they believe that the harm caused by climate change impacts will be substantial, rather than just moderate.