Historians of science can benefit from thinking more deeply about land. Scholarly emphasis on the geographies of scientific knowledge has become pervasive since the “spatial turn” of the late 1990s. At the same time, the history of science has increasingly intersected with environmental history. Despite these growing connections, historians of science have been slow to embrace a core concern of environmental history: land. While space and place now have a rich literature in the historiography of science, land appears in histories (...) of science in more scattered, incidental ways – largely as a place where science may occur or be applied. More than just a unit of ground, land is analytically connected to a web of questions about labor, property, governance, identity, and environmental change explored by environmental historians, geographers, and political ecologists. This article examines what historians of science – particularly, but not exclusively, historians of the field and environmental sciences – have to gain by taking land more seriously. A reexamination of the Rain Forest Project, a radioecology study initiated by systems ecologist Howard Thomas Odum in what is today El Yunque National Forest, Puerto Rico, serves as a case in point. Viewing this field site as land reframes ecologists’ fieldwork as a form of land use, highlighting its place within regimes of land tenure, its connections with other communities’ uses of the land, and its persistent local legacies. (shrink)