High incidence of brain and other nervous system cancer identified in two mining counties, 2001-2015

•When comparing age group specific incidence rate ratio (IRR) for DL/SB versus comparison counties, we found an IRR for DL/SB of 6.28 for children ages birth to 4 years, and an IRR of 3.95 for adults age 30-34 years.•Brain and other nervous system cancers incidence for residents of DL/SB ages 0-4 years is 1.54/10,000 person years compared to 0.24/10,000 person years in the remaining counties in Montana. Similarly, incidence of brain and other nervous system cancer for residents of SB/DL aged 30-34 years is 1.84/10,000 person years compared to 0.47/10,000 person years.•Further research is needed to explore associations between metal exposures and brain and other nervous system cancers, that includes residential history, exposure to radiation, family history of conditions associated with brain and nervous system cancer, and other known risk factors.