In the 1840's, Montgomery founder Daniel S. Gray dug a mill race through the center of what is now Montgomery Park and built a dam across the Fox River south of Taylor Street using excavated stone. After the dam and mill race were finished, he used the remaining stone to build a machine shop and foundry and a header and reaper factory on the mill race north of the bridge, taking advantage of water as the primary source of power in the early days of powered machinery. A 5-story stone flouring mill was built in 1853 on the same mill race after it was extended farther south, and by 1860 the Palmer brothers had built a blind and sash factory near the dam. For many decades, the three mills north of the bridge and the large flour mill south of the bridge formed the industrial focus of the community. By the turn of the century, electricity was replacing waterpower, and the mills north of the bridge were abandoned and fell into disrepair. Daniel Gray's old reaper factory burned in the 1890's. In the 1930's, the remnants of the old mills were dismantled, and their stones were used to build a retaining wall along the river as part of a Works Progress Administration project during the Great Depression. The mill race was filled in, but over time it settled, and the outline of its former course remained visible in the depressed area through the center of Montgomery Park.