The Building Bridges planning initiative focused on preparing sites to establish effective linkages between jails and community-based treatment settings in order to deliver medications for opioid use disorder (MOUD) to justice-involved people. This 9-month planning initiative was jointly funded and led by the Bureau of Justice Assistance (BJA) and Arnold Ventures. Building Bridges was designed to assist local communities by: increasing stakeholder understanding of promising practices in the use of MOUD in jails and community-based settings; developing effective partnerships between jails and community-based treatment providers; building a comprehensive plan for initiating or expanding an MOUD continuum of care model from jail to the community; and planning for continuity and coordination of MOUD during transitions into jails and reentry into communities.