In the late 1990s, the US Navy found itself defending the use of long-range sonar in court after a series of widely publicized mass strandings of whales in areas of the ocean that were then being used by the Navy to test new sonar systems. In these lawsuits, a wide range of plaintiffs – a whale-watching tour company, the Hawai’i Green Party, various environmental non-governmental organizations (NGOs), even dolphins and whales themselves – sought injunctions and restraining orders which would limit the Navy’s use of sonar and thus prevent harm to wildlife. The environmental NGO National Resources Defense Council launched the most successful of these lawsuits in California and Hawai’i under various American environmental law statutes. In this chapter, I suggest that sonar litigation has become a key site in struggles over regimes of remote sensing – that is, the institutional practices, rules and infrastructures that organize the senses and their technological extensions for the purpose of monitoring and intervening in distant spaces and events. Although the ostensible purpose of high-powered naval sonar is to protect the US and its allies from a new generation of ultra-quiet dieselelectric submarines, I suggest that the longer-term impact of acoustic remote sensing has been the creation and governance of new kinds of territories and subjectivities in ocean sound. I focus on Natural Resources Defense Council v. Evans ,1 which was the most successful anti-sonar lawsuit to date in the sense that the court accepted many of the environmental groups’ claims regarding the harmful potential of military sonar. Although sonar litigation continued after this case, and NGOs lost much of the ground they had gained in Evans , this case brings into focus the struggle over sensory regulation in the ocean as subsurface space becomes increasingly central to capitalist expansion and geopolitical confl ict.