An unprecedented analysis of the origin story of New Mexico's modern water management system. Maria Lane's Fluid Geographies traces New Mexico's transition from a community-based to an expert-led system of water management during the pre-statehood era. To understand this major shift, Lane carefully examines the primary conflict of the time, which pitted Indigenous and Nuevomexicano communities, with their long-established systems of irrigation management, against Anglo-American settlers, who benefitted from centralized bureaucratic management of water. The newcomers' system eventually became settled law, but water disputes have continued throughout the district courts of New Mexico's Rio Grande watershed ever since. Using a fine-grained analysis of legislative texts and nearly two hundred district court cases, Lane analyzes evolving cultural patterns and attitudes toward water use and management in a pivotal time in New Mexico's history. Illuminating complex themes for a general audience, Fluid Geographies helps readers understand how settler colonialism constructed a racialized understanding of scientific expertise and legitimized the dispossession of nonwhite communities in New Mexico.