In around 1835, John Reed built a sawmill on Mill Creek. The saw that he obtained from the Russians at Fort Ross was powered by an undershot water wheel driven by water flowing in the creek. He built a dam upstream for a pond that stored water for use during periods of slack creek flow. By 1909, there was a concrete dam in the creek upstream from the bridge in Old Mill Park. The pool behind it was a popular swimming hole. It was deep enough for diving in places and shallow enough for wading in other places. In 1939, the Mill Valley Record reported that on one day, there were about 150 kids playing in the pool. In the late 1960s and early 1970s, the Mill Valley Optimist Club stocked the pool with 2000 rainbow trout. Boy Scout Troop 34 would stand guard to make sure no fish were taken until the official two-day Trout Fishing Derby took place. Anyone who caught one of the 25 trout that had been tagged received a special prize. There is currently a concrete diversion dam in place that may have been part to the trout pool dam.