"One of the main reasons the Pilgrims decided to locate in Plymouth is the waterway that is referred to today as Town Brook. Town Brook is a small river that runs through the center of Plymouth for a mile and a half and empties into the harbor next to Plymouth Rock. On this river you will find the recreation of the Jenney Grist Mill built on the location of the first mill built in the United States. The mill is operational and runs the same as it did when it was originally built in 1636.
The Pilgrims found this river important for three reasons. The first is that over the rivers mile and a half run it drops 80 feet in elevation allowing for ample waterpower. The second is that the river and the pond that feeds it are spring fed so that even in times of drought, the river never runs out of water. The third is that the river supplied the Pilgrims with their fertilizer. Every spring fish called herring migrate from the ocean up to the pond to spawn. On the way by the mill the Pilgrims would take the fish from the river and plant them in the sandy ground to fertilize for the planting of the corn. To this day, over a six-week period, thousands of fish go up this fish ladder to spawn.
John Jenney, who built the mill in 1636, changed the quality of life for the Pilgrims.By grinding corn with water power, it was easier to feed the increasing population. The building of the mill was also instrumental in the establishment of the free market system. Eventually there were over 14 mills built on this river contributing to the beginning of industry in the United States."