Deer Lake is a borough in Schuylkill County, Pennsylvania. The population was 670 at the 2020 census. The mayor of the borough is Larry Kozlowski. The community was founded as a resort community serving coal barons and other members of the wealthy elite of nearby Pottsville. A small summer stock theatre operated during the 1920s, in which actors suc…Deer Lake is a borough in Schuylkill County, Pennsylvania. The population was 670 at the 2020 census. The mayor of the borough is Larry Kozlowski. The community was founded as a resort community serving coal barons and other members of the wealthy elite of nearby Pottsville. A small summer stock theatre operated during the 1920s, in which actors such as John Kenley performed.