What are the preferences of local elected officials toward joint land use planning, a type of interlocal cooperation and form of regional governance? And how do we explain these preferences? The literature on interlocal cooperation depicts public officials as rational opportunists whose preferences and behaviors can be reliably predicted by institutional attributes of the municipal, intermunicipal, and political context in which they serve—i.e., where material benefits to the municipality or to the local official outweigh costs, cooperation will arise and endure. I propose that in policy areas where local benefits are uncertain and local autonomy is at risk, thought processes are significantly affected by individually held cultural values. I specify a cultural cognition of governance hypothesis, in which variation in individuals’ preferences toward interlocal cooperation is a result of variation in measurable dispositions toward solidarity (versus individualism) and equality (versus differentiation). I test the hypothesis using data on 538 local elected officials representing 262 Michigan municipalities in the Detroit and Grand Rapids metropolitan areas. The dependent variables are measures of preferences toward four types of agreement made under the state’s Joint Municipal Planning Act of 2003 (;;JMPA”). The JMPA is flexible, allowing agreements that cover from a few parcels of land to entire municipalities, and from a merely advisory planning commission to a complete merger with dissolution of existing local planning and zoning functions. The legislation, therefore, presents a unique opportunity for probing local elected officials’ preferences toward land use cooperation under multiple adoption and implementation scenarios. Independent variables are constructed from survey data on local elected officials’ cultural dispositions, political perceptions, and individual level controls, and from municipal level census and fiscal data. Based on analysis with hierarchical linear modeling, findings provide strong support for the cultural cognition of governance hypothesis. The findings speak to the prospects for regional governance and the understanding of collaboration and social learning in planning processes.