Big Boulder Lake B, located in Kidder Township, Pennsylvania, is a privately owned dam regulated by the Pennsylvania Department of Environmental Protection. Built in 1957, this Earth-type dam primarily serves for recreational purposes with a normal storage capacity of 920 acre-feet. The dam stands at 18.5 feet tall and spans 415 feet in length, impounding Swamp Run and covering a surface area of 170 acres.

With a high hazard potential, Big Boulder Lake B has undergone regular inspections, with the most recent one conducted in January 2021, resulting in a satisfactory condition assessment. Despite its recreational focus, the dam also supports water supply purposes, showcasing its dual functionality and importance in the region's water resource management. Climate and water resource enthusiasts will find this structure intriguing for its historical significance and environmental impact in the Carbon County area of Pennsylvania.