Indian Mountain Lake is a census-designated place in Carbon County and Monroe County, Pennsylvania. It is part of Northeastern Pennsylvania. The Carbon County portion of the CDP is located in Penn Forest Township, while the Monroe County portion is in Tunkhannock and Chestnuthill townships. As of the 2020 census, the population of the community w…Indian Mountain Lake is a census-designated place in Carbon County and Monroe County, Pennsylvania. It is part of Northeastern Pennsylvania. The Carbon County portion of the CDP is located in Penn Forest Township, while the Monroe County portion is in Tunkhannock and Chestnuthill townships. As of the 2020 census, the population of the community was 4,733. There are 3,262 single-family residential building lots in the community as of 2020 records.