The >1000-km-long transform fault defining the continental western boundary of the Indian plate (Fig. 1) is named after the town of Old Chaman (30.85° N, 66.52° E) that was damaged by an 6:5 < M w < 6:7 earthquake there in 1892 (Griesbach, 1893). We quantify slip and afterslip in the 1892 earthquake from historical reports of rail offsets and rotation, and estimate rupture length from survey reports. We estimate that total slip exceeded 1 m, similar to the current potential slip deficit now prevailing on the fault derived from recent Interferometric Synthetic Aperture Radar and Global Positioning System studies. As a consequence, a recurrence of the 1892 earthquake could soon occur. In 1892, the population of Chaman numbered less than 1000. The present population of Chaman and nearby villages exceeds 0.5 million.