The present work provides a detailed analysis of chain formation and locality conditions imposed on it within the Minimalist Program. It does so by analyzing resumptive strategies in great detail. This study claims that resumptive pronouns and their antecedents are first merged as constituents, and are separated via movement (thus forming instances of discontinuous constituents). Resumptive chains are thus akin to the well-known stranding analysis of quantifier float. A taxonomy of islands is developed that crucially ties barriers for movement to agreement possibilities. The stranding of a resumptive pronoun is shown to limit the role of agreement for the moving element, thereby allowing a chain to be formed across an island.