DOD has reported to Congress since fiscal year 2004 on several items related to its training ranges in response to section 366 of the Bob Stump National Defense Authorization Act for Fiscal Year 2003. The act as subsequently amended required annual progress reports to be submitted at the same time as the President submitted the administration’s annual budget for fiscal years 2005 through 2018. The provision that we evaluate the plans submitted pursuant to section 366 within 90 days of receiving the report from DOD has also been extended through fiscal year 2018. In our prior reviews of DOD’s Sustainable Ranges Reports, we found that DOD did not address certain required elements when it initially submitted its comprehensive plan in 2004. Further, we noted that it took DOD some time to develop a plan consistent with the basic requirements of section 366. Over time, we found that as DOD reported annually on its progress in implementing its comprehensive plan, it continued to improve its Sustainable Ranges Reports, and it has reported on the actions it has taken in response to prior GAO recommendations. Specifically, in 2013 we reported that DOD had implemented all 13 of the recommendations we had made since 2004 for expanding and improving DOD’s reporting on sustainable ranges. Further, DOD has progressed from using four common goals and milestones to using seven shared goals for which the services have developed their own actions and milestones that are tailored to their missions. We have reported that these new goals and milestones are more quantifiable and now are associated with identified time frames. DOD’s 2017 Sustainable Ranges Report met the annual statutory reporting requirements to describe DOD’s progress in implementing its sustainable ranges plan and any actions taken or to be taken in addressing constraints caused by limitations on the use of military lands, marine areas, and airspace. In its 2017 report, DOD provided updates to the plan that were required by the act. These updates included: (1) proposals to enhance training range capabilities and address any shortfalls in current resources; (2) goals and milestones for tracking planned actions and measuring progress in the implementation of its training range sustainment plan; and (3) projected funding requirements for implementing its planned actions. In our review of DOD’s 2017 Sustainable Ranges Report, we found that, as required by statute, DOD reported on its proposals to enhance training range capabilities and address any shortfalls in resources. DOD developed these proposals by evaluating current and future training range requirements and the ability of current DOD resources to meet these requirements. In its 2017 report, DOD revalidated its 2015 individual range capability and encroachment assessments and the current and future military service training range requirements. To do so, DOD updated the report sections pertaining to each military service’s issues related to range capability, encroachment, and special interests to the military service. For instance, regarding the Marine Corps, the report noted, among other things, that the Marine Corps has identified the need for an aviation training range on the East Coast of the United States capable of supporting precision-guided munitions training. The report states that the Marine Corps selected the expansion of Townsend Bombing Range in Georgia as the best alternative for securing this East Coast capability after a thorough assessment of area capabilities. The report notes that a record of decision to expand Townsend was signed in January 2014, and that a formal airspace proposal supporting the land expansion has been submitted to the Federal Aviation Administration. The report further stated that full operational capability is now planned for December 2019. In its 2017 report, DOD also reported on seven evolving activities and emerging issues, all of which were reported in its 2016 report. These seven activities and issues were as follows: (1) new sustainable range initiative-related influences and actions; (2) budget reductions impacting range capability; (3) foreign investment and national security; (4) threatened and endangered and candidate species; (5) demand for electromagnetic spectrum; (6) continued growth in domestic use of unmanned aircraft systems; and (7) offshore energy. DOD’s 2017 report outlined some actions being taken to mitigate the challenges these issues may present for DOD test and training ranges. For example, in response to new sustainable range initiative-related influences, DOD responded to a recommendation in Senate Armed Services Committee Report 114-49 to include a review of the general capabilities, critical issues, and future capabilities necessary to support Special Operations Forces (SOF) range requirements. The 2017 Sustainable Ranges Report is the first to incorporate SOF-specific range issues. Foreign investment and its effects on national security continue to be an evolving issue faced by DOD. In an April 2016 report, we evaluated the extent to which DOD made progress in its efforts to assess the national security risks and effects of foreign encroachment. In that review, we found that DOD had made limited progress in addressing foreign encroachment on federally managed land since we had last reported on the subject in December 2014. We also found that DOD has begun to take some steps toward assessing the national security risks and effects of foreign encroachment, but had not yet fully implemented the recommendations from our December 2014 report, which were as follows: (1) that DOD should develop and implement guidance for conducting a risk assessment on foreign encroachment and (2) that DOD should collaborate with other federal agencies to obtain additional information on transactions near ranges. DOD concurred with both recommendations. According to the 2017 report, DOD is pursuing opportunities to obtain information related to foreign investment and transactions in proximity to DOD mission-essential locations from agencies with land management authority as well as conducting a risk assessment related to those locations. In addition, DOD reported that it is considering seeking legislative relief to enhance data-collection and data- sharing practices regarding foreign investment in the proximity of DOD mission-essential locations as an avenue to mitigate national security- related encroachment, and it has engaged the various federal land managers to expound on potential issues related to DOD concerns. In its 2017 Sustainable Ranges Report, DOD used goals and milestones to address the statutory requirement to describe its progress in implementing its comprehensive training range sustainment plan. DOD has seven goals, as follows, in support of this plan: (1) mitigate encroachment pressures on training activities from competing operating space; (2) mitigate electromagnetic spectrum competition; (3) meet military airspace challenges; (4) manage increasing military demand for range space; (5) address affects resulting from new energy infrastructure and renewable energy; (6) anticipate climate change effects; and (7) sustain excellence in environmental stewardship. Using these goals as a common framework, each military service developed its own milestones and needed actions for reaching those milestones. In DOD’s 2017 Sustainable Ranges Report, each service provided updates to its milestones and actions based on annual assessment data. The report included the following examples: The Army has ongoing actions to mitigate electromagnetic spectrum competition on ranges. For example, the Army reported that installation of fiber optic cabling has been completed at approximately 20 installations to support wireless networks and targeting control systems in order to mitigate electromagnetic spectrum interference on ranges. The Navy has ongoing interactions with Bureau of Ocean Energy Management state renewable energy task forces to support assessments of proposed wind energy developments to minimize effects on Navy and DOD offshore readiness. The Marine Corps has ongoing actions to engage in regulatory and legislative processes at the local, state, and national levels on issues that may affect range sustainability or readiness. The Marine Corps is also exploring partnerships to meet natural resource regulatory responsibilities. The Air Force is engaged in ongoing development of the Center Scheduling Enterprise flight scheduling system for use at Air Force Ranges. In addition, the Air Force is developing an interface between its flight scheduling system and the Army/Marine Corps Range Facility Management Support System, to facilitate scheduling across military services. In the 2017 Sustainable Ranges Report, DOD met the statutory requirement to track its progress in implementing the comprehensive plan by identifying the funding requirements needed to accomplish its goals. DOD delineated the following four funding categories to be used by the services to project their range sustainment efforts: (1) modernization and investment; (2) operations and maintenance; (3) environmental; and (4) encroachment. The funding requirements section of the 2017 report includes descriptions and specific examples for each funding category, as well as actual funding levels for fiscal year 2016 and requested funding levels for fiscal years 2017 through 2021. For example, the encroachment category is described as funding dedicated to actions optimizing accessibility to ranges by minimizing restrictions that do or could limit range activities, including outreach and buffer projects. Specific examples of encroachment funding include Army Compatible Use Buffer program administration and support and encroachment planning efforts. The report also provides an explanation of any fluctuations occurring over the 5-year funding period covered in the report. For example, the Air Force’s requested funding for the modernization and investment category fluctuated from $48.3 million in fiscal year 2017 to $236.8 million in fiscal year 2020 to $185.6 million in fiscal year 2021. The Air Force attributes this planned fluctuation to a decision to infuse funding in range infrastructure to research, develop, procure, and sustain advanced threat emitters, range communications/networks, and datalink systems, among other things. We are not making recommendations in this report. In oral comments on a draft of this report, DOD agreed with our findings and did not have any further comments. We are sending copies of this report to the appropriate congressional committees; the Secretary of Defense; the Secretaries of the Army, Navy, and Air Force, and Commandant of the Marine Corps; and the Deputy Assistant Secretary of Defense for Readiness. In addition, the report is available at no charge on the GAO website at http://www.gao.gov.