The Los Angeles River is big. Flowing 90 kilometres from headwaters in the sprawling suburbs to its mouth beside America’s second-busiest port, the river is shaped by 3.5 million barrels of cement, and tens of thousands of tons of steel and stone. A mid-twentieth century channelisation project saw the United States Army Corps of Engineers transform the river in what has become one of America’s most conspicuous flood control projects. The river’s foremost advocacy organisation calls it “one of the largest conceptual earthworks ever.” The extreme scale and scope of the river’s alteration has not obscured the relational exchange between human beings and the rest of nature but instead illuminates it brightly. Intimacy is an emotional entanglement, and a way of seeing, writing and thinking about place. Oral histories and archival research are used in this paper to explore large-scale urban infrastructure at a tiny, intimate human scale. Stories from fishers, graffiti artists, public officials, advocates, politicians, architects, curators, and kayakers transform existing river historiographies. Doing so attests to the importance of nature-connectedness in urban landscapes, and the tensions that emerge as political and popular attention begins to move a place from the margins to the mainstream.