The Appalachian Trail Centennial Act seeks to enhance the preservation, maintenance, and management of national historic and national scenic trails, recognizing their role as vital landscape conservation tools. It emphasizes that trail conservation is built on partnership, collaboration, and community engagement, highlighting the Appalachian National Scenic Trail as a model for cooperative management. The bill aims to strengthen this cooperative model, especially in light of the Appalachian Trail Conservancy's centennial in 2025. A core provision establishes Designated Operational Partners for covered trails, with the Appalachian Trail Conservancy specifically designated for the Appalachian National Scenic Trail within one year of enactment. For other trails, the Secretary concerned may designate eligible non-profit entities that demonstrate experience, a plan for volunteer coordination, and financial adherence. These partners are recognized for their unique expertise and can receive appropriated funds without competition, facilitating their operational roles. These Designated Operational Partners gain significant responsibilities, including developing proposed priority lists for land and resource protection to guide federal funding decisions for land acquisition. They can also accept or reject proposed comprehensive plans and amendments for their respective trails. Federal agencies are authorized to transfer surplus personal property to these partners for trail-related activities and are directed to enter into cooperative agreements, up to 20 years, delegating operational and management responsibilities. While the Federal Government retains administrative authority, it must encourage volunteer participation and remedy constraints on their roles. Covered trails are made eligible for various federal funding streams, including the Land and Water Conservation Fund , and are considered units of the National Trails System for funding purposes. The Act also improves trail planning by requiring visitor capacity determinations based on specific segments and mandates periodic economic impact assessments on gateway communities . Finally, it requires reports to Congress on trail development challenges and successes, emphasizing community engagement.