High Quality Content by WIKIPEDIA articles! Lake Coeur d`Alene is a natural lake in the Idaho Panhandle, located in the vicinity of the city of the same name. It spans 25 miles (40 km) long, ranges from 1 to 3 miles (4.8 km) wide and has over 109 miles (175 km) of shoreline for boaters and vacationers to explore and enjoy.