People's judgments about property shape how they relate to other people with respect to resources. Property law cases can provide a valuable window into ownership judgments because disputants often use conflicting rules for ownership, offering opportunities to distinguish these basic rules. Here we report a series of ten studies investigating people's judgments about classic property law cases dealing with found objects. The cases address a range of issues, including the relativity of ownership, finder versus landowner rights, object location, objects below- versus above-ground, mislaid versus lost objects, contracts between landowners and finders, and the distinction between public and private space. The results show nuanced patterns in ownership judgments that are not well-explained by previous psychological theories. Also, people's judgments often conflict with court decisions and legal principles. These empirical patterns can be used to generate and test novel hypotheses about the intuitive logic of ownership.