This chapter examines the ways in which nature has been conceptualized to define nationhood and citizenship. It builds upon the earlier works on colonial science during the US-occupied Philippines by underscoring the role of nature education in cultivating scientific thinking, citizenship, and nationhood. Inquiring into state instrumentalities such as public education, the paper illustrated how the promotion of scientific understanding of the “Filipino” environment reflected the colonial agenda for cultural reorientation and national imagination. I argue that the “scientific” conceptualization of Philippine natures along notions of nationhood provided the fundamentals of environmentalism.