As identified by the U.S. Congress, there is a national need for collaborative approaches to digital preservation services for cultural, historical, and political repositories. Responding to this need, the Library of Congress established the National Digital Information Infrastructure and Preservation Program (NDIIPP) in 2003 to produce a "national network of partners collaborating on digital preservation" that would pioneer a variety of digital preservation services for cultural memory organizations. Among these collaborative ventures, the MetaArchive Initiative developed an organizational model and operated a technical infrastructure (building on the LOCKSS software developed at Stanford University) for preserving the digital assets of cultural memory organizations in a geographically distributed framework. Subsequently, MetaArchive transitioned from a project to a program with the founding of the MetaArchive Cooperative in 2007. This article focuses upon the relationship between MetaArchive and NDIIPP, highlighting MetaArchive's commitment to enable institutions to host their own preservation solutions rather than outsourcing this core mission. It details the strategies that the MetaArchive Cooperative has employed to support, sustain, and grow its cross-institutional collaboration; explores an array of logistical and organizational issues that have arisen; and discusses the strengths of particular organizational structures for fostering and sustaining collaborative work between peer institutions.