Boulder Creek is named for the Creek that runs through the north end of the town. Boulder Creek served as the upper terminus of the San Lorenzo Valley Logging Flume, which began construction in 1874 and when formally opened in October 1875 was augmented by a new rail line to transport logs to the wharf in Santa Cruz. In the 1880s, this lumber town which was called Lorenzo took the name of the Boulder Creek post office that had been established in the 1870s.