2020 census As of the
2020 census, Moon Lake had a population of 4,817. The median age was 43.7 years. 19.1% of residents were under the age of 18 and 16.1% of residents were 65 years of age or older. For every 100 females there were 108.0 males, and for every 100 females age 18 and over there were 110.6 males age 18 and over. 91.1% of residents lived in urban areas, while 8.9% lived in rural areas. There were 1,947 households in Moon Lake, of which 23.7% had children under the age of 18 living in them. Of all households, 36.3% were married-couple households, 26.5% were households with a male householder and no spouse or partner present, and 24.4% were households with a female householder and no spouse or partner present. About 29.6% of all households were made up of individuals and 10.8% had someone living alone who was 65 years of age or older. There were 2,215 housing units, of which 12.1% were vacant. The homeowner vacancy rate was 3.2% and the rental vacancy rate was 8.2%. ==References==