ItemBuilder Borders on Aboriginal Lands(2019)During the nineteenth and early twentieth centuries, the United States and Canada expended significant effort demarcating and enforcing their shared border. The surveying process began in the east, transitioned to the Pacific Coast, and concluded along the Great Plains. For much of the nineteenth century, both Britain (later Canada) and the United States claimed far more territory than they controlled in practice. Marking the border proved easier than enforcing it. Both countries relied on a wide assortment of personnel to enforce their divide, including those drawn from customs, immigration, Indian Affairs, the North West Mounted Police, military, and local police forces. The reliance on such a wide assortment of independent agencies led to infighting, confusion, and widespread inconsistencies. Many of these agencies had explicit mandates that differed from one another and, for some, border control represented only a portion of their broader duties. The geographic distribution of each of these departments, moreover, meant that the border looked quite different in each region. As these departments grew and shrank, the border changed with them. In a practical sense, the border represented a wall of uneven heights. Time period, geographic location, the zealousness of the local agents, and the demography of the region all impacted what the border looked like. Racial prohibitions towards Chinese immigration and the distinct legal status of Indigenous peoples added an additional layer of complexity. The Sioux, Nez Perce, Coast Salish, Blackfoot, Cree, Métis, Chinese, African Americans, and Europeans all experienced different borders from one another in both a legal and practical sense. The Building Borders on Aboriginal Lands Project provides a quantitative and geospatial backbone to understand how Canada and the United States exerted control over their shared border. The project maps federal power and engagement between 1860 and 1924 as people were hired and fired and as posts were built and fell into disrepair. The project consists of personnel and post records for each of the major agencies who patrolled the border as well as their patrol routes where available. Finally, this project digitized the survey records for the Pacific Coast. The border survey process was not possible without the contributions of hundreds of Indigenous guides, packers, and transporters, many of whom appeared in the special paylist section of that report.