In 1857 Californians experienced the largest earthquake in the state’s history. Few people lived near the earthquake’s epicenter, so the earthquake was small in terms of damage and loss of life, but it still was felt from San Diego to San Francisco. After the earthquake, Californians wanted to understand what had happened elsewhere. They circulated narratives about the earthquake by boat and horseback in letters and newspapers. Californians made sense of the earthquake without standardized timekeeping or modern scientific theories. The descriptions and explanations of the earthquake that surfaced were shaped by and reflected the 1857 information infrastructure.