During the 1990 Manjil, Iran, earthquake (MS = 7.7), an estimated 35,000 people lost their lives and more than 300,000 were left homeless. The earthquake ground shaking caused enormous destruction of unreinforced structures. In addition, widespread liquefaction contributed significantly to building damage in towns as far away as 85 km from the ruptured fault. Following the earthquake, the authors surveyed the liquefaction regions, conducted geotechnical field explorations, and documented case histories on liquefaction of level ground, liquefaction-induced building settlement, permanent ground displacement, and performance of piles and piers in liquefied soils. This article presents and discusses the data of the case histories investigated. In addition, based on the evidence from the Manjil earthquake, the importance of geologic input in mapping of liquefaction potential in earthquake-prone regions is demonstrated. In the companion article, the authors present the results of their analyses of liquefaction-related case histories.