The Nevada Test Site Environmental Report 2009 was prepared to meet the information needs of the public and the requirements and guidelines of the U.S. Department of Energy (DOE) for annual site environmental reports. It was prepared by National Security Technologies, LLC (NSTec), for the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office (NNSA/NSO). This and previous years' Nevada Test Site Environmental Reports (NTSERs) are posted on the NNSA/NSO website at http://www.nv.doe.gov/library/publications/aser.aspx. This NTSER was prepared to satisfy DOE Order DOE O 231.1A, "Environment, Safety and Health Reporting." Its purpose is to (1) report compliance status with environmental standards and requirements, (2) present results of environmental monitoring of radiological and nonradiological effluents, (3) report estimated radiological doses to the public from releases of radioactive material, (4) summarize environmental incidents of noncompliance and actions taken in response to them, (5) describe the NNSA/NSO Environmental Management System and characterize its performance, and (6) highlight significant environmental programs and efforts. This NTSER summarizes data and compliance status for calendar year 2009 at the Nevada Test Site (NTS) and its two support facilities, the North Las Vegas Facility (NLVF) and the Remote Sensing Laboratory (RSL)-Nellis. It also addresses environmental restoration (ER) projects conducted at the Tonopah Test Range (TTR). Through a Memorandum of Agreement, NNSA/NSO is responsible for the oversight of TTR ER projects, and the Sandia Site Office of NNSA (NNSA/SSO) has oversight of all other TTR activities. NNSA/SSO produces the TTR annual environmental report available at http://www.sandia.gov/news/publications/environmental/index.html.