Proponents of the Anthropocene epoch posit that human activities now powerfully influence the earth’s governing systems. Many environmental scholars have offered alternative concepts for this new geologic epoch to challenge its outward anthropocentrism and tendency to flatten the diversity of the world’s people into a single planetary humanity. But in doing so, these critiques distort a more distributive and systemic understanding of agency. This chapter suggests that “geophysical agency” offers historians a more useful and precise conceptual term for interpreting connections among human ideas and actions, material systems, and geological change. One way that human undertakings have functioned geologically has been by moving earth and inscribing asphalt over an extended chronology of the Great Acceleration. Examining 1930s highway construction in Colorado’s Big Thompson Canyon offers a window into some of the historical processes that have defined geophysical agency.