The Spallation Neutron Source (SNS) is an accelerator-based neutron source being built in Oak Ridge, Tennessee, by the U.S. Department of Energy. The SNS will provide the most intense pulsed neutron beams in the world for scientific research and industrial development. At a total cost of $1.4 billion, construction began in 1999 and will be completed in 2006 the culmination of the collaborative efforts of six National Laboratories. An overview of the contribution of these laboratories is provided specifically addressing the design and construction of the numerous vacuum systems and their integration into an operational facility (N. Holtkamp, The SNS Linac and Storage Ring: Challenges and Progress Towards meeting them, EPAC 2002). (c) 2005 American Vacuum Society.