Determining good boundaries for governance jurisdictions is among the most difficult problems in political theory and political philosophy. But to whom the rules of a given jurisdiction applies is a problem that afflicts private as well as public governance. Clubs have boundaries no less than cities, states, or nations. This essay applies Hayek’s conception of competition as a discovery procedure to boundary problems, arguing that good jurisdictional boundaries are subject to a great deal of contingent variation according to particular the conditions of time and place. Philosophical speculation, therefore, cannot fully replace a trial and error process that facilitates social learning about where good boundaries fall. I outline the features of good boundaries that make them subject to such variation, then evaluate two criteria for evaluating whether existing jurisdictional boundaries are good: one that emphasizes ex ante consent to boundaries, and one that focuses on the ability of individuals to exit from jurisdictions ex post, arguing that the exit-focused approach is underappreciated.