For a short time, Pacheco had a lot of very successful businesses. During that time, ships from the Pacific Ocean were able to get to the town by going through Pacheco Slough. Then, during the 1860s, there were some fires, floods, and an earthquake. These destroyed the town and filled the slough with silt so that ships could not get there any more. Many people later left Pacheco to go to the nearby town of Todos Santos, which was later renamed to Concord.