The Shenandoah Valley Civil War Sites Study Act of 1990 permitted the National Park Service (NPS) to investigate which unprotected battlefields (I5) might be preserved. After collaboration with the NPS, I was allowed to research the battlefield site of Opequon Creek (Third Battle of Winchester) in Frederick County, Virginia. In return, the NPS would receive a copy of this thesis for their use. A questionnaire, submitted to local residents, determined if a park was wanted, what type of park it might be, and what programming activities would be selected. A combination park of recreation, historical, and natural definitions was developed on the residents desires. The Opequon Creek Park process was developed first to alleviate any pre-NPS planning process influences. After Opequon Creek Park was designed, a process comparative analysis was made with the existing NPS model of Antietam Battlefield Park located in Sharpsburg, Maryland. The analysis determined if the NPS's planning process needed refinement. The NPS uses the "Planning Process Guidelines, NPS-2, 1985", to create each park's General Management plan (GMP). Two participatory stages, open houses and public hearings, were found mid-way through the development of Antietam's GMP. The Opequon process allows for participatory input at the start of park development but, did not allow for post design comments. Antietam's park definition was determined before public input was solicited and used based on early project funding requirements. The Opequon process, if implemented immediately upon a new parks legal creation, would save the NPS time and money in the research and development of new parks. Future parks will be carved from urbana as America's population doubles by 2038. The NPS needs a refined participatory planning method to do business with the public of today, the shrinking budgets of tomorrow, and the preservation of needed green space in the future. / Master of Landscape Architecture