|Elevation||1,329 ft (405 m)|
|Time zone||EST (UTC-5)|
|o Summer (DST)||EDT (UTC-4)|
Frederick Charles Brenckman wrote in 1913:
The region about Lake Harmony has in recent years become quite popular as a summer resort. Numerous cottages or bungalows have been erected, principally by people from Mauch Chunk and Allentown, while many, lured by the cool breezes and quietness of the retreat, spend a portion of the heated term of each year as campers on the shores of the lake.
According to the United States Census Bureau, ZIP code 18624 has a total area of 16.9 square miles (43.9 km2), of which 16.5 square miles (42.7 km2) is land and 0.46 square miles (1.2 km2) is water.
Lake Harmony is neither an incorporated area nor a census-designated place, all the data is for the ZIP code 18624. As of the census of 2010, there were 718 people, 359 households, and 203 families residing in the community. The population density was 43.5 people per square mile (6.6/km²). There were 1,594 housing units at an average density of 96.6/sq mi (12.3/km²). The racial makeup of thecommunity was 95.8% White, 1.7% African American, 0.1% Native American, 0.7% Asian, 1.0% from other races, and 0.7% from two or more races. Hispanic or Latino of any race were 3.1% of the population.
There were 359 households, out of which 14.8% had children under the age of 18 living with them, 46.8% were married couples living together, 5.6% had a female householder with no husband present, and 43.5% were non-families. Out of all the households, 7.5% had someone living alone who was 65 years of age or older. The average household size was 2.0 and the average family size was 2.61. 69.95 of the housing units were for seasonal, recreational, or occasional use.
In the community the population was spread out, with 14.4% under the age of 18, 4.7% from 19 to 24, 18.2% from 25 to 44, 37.4% from 45 to 64, and 25.3% who were 65 years of age or older. The median age was 52 years. The gender distribution was 52.9% male and 47.1% female.
According to the American Community Survey in 2013, the median income for a household in the community was $61,563, and the median income for a family was $62,500.