Hayden Lake is a city in Kootenai County, Idaho, United States. Located in the northern portion of the state, it is considered a suburb of the city …Hayden Lake is a city in Kootenai County, Idaho, United States. Located in the northern portion of the state, it is considered a suburb of the city of Coeur d'Alene. Its population was 574 at the 2010 census. The city was named after the nearby Lake Hayden, which is now more commonly also known as Hayden Lake, after the city.