The North Central Texas Council of Governments (NCTCOG) is a non-regulatory, voluntary association of, by, and for over 230-member governments in a 16-county region, including the rapidly growing Dallas-Fort Worth Metroplex, with a population exceeding 7 million people. Through the Metroplex flows the Clear Fork, West Fork, and Elm Fork of the Trinity River, all of which converge into the Trinity River main stem that flows through Dallas. Although flood control infrastructure is provided by multiple entities, there is no unified regulatory flood control district within the North Central Texas (NCT) region. The NCT region is also unique in that within it resides the United States Army Corps of Engineers (USACE) Fort Worth District office, the Federal Emergency Management Agency (FEMA) Region 6 office, and regional river authorities and water districts. These agencies are members of the Trinity Common Vision Program, a 30-year cooperative effort of entities along the Trinity River that, alongside other program goals and initiatives, works to conserve the flood storage of the Trinity River and its branches through the Corridor Development Certificate (CDC) process. As rural areas of the NCTCOG region begin experiencing population gains, a unique opportunity is present to avoid loss of valuable flood storage in other branches of the Trinity River. The East Fork Trinity River is located in one of the fastest growing areas of the region, yet much of it was only mapped as Zone A. Through partnerships with FEMA Region 6, the USACE Fort Worth District, and current and prospective Trinity Common Vision members, a portion of the East Fork Trinity is joining the Trinity River Common Vision Program. This presentation will focus on the extensive multi-jurisdictional collaboration and communication efforts that have facilitated the first geographic expansion since the program’s inception.