Heilwood is a census-designated place (CDP) in Indiana County, Pennsylvania. The population was 711 at the time of the 2010 census.
Heilwood is located at 40°38′14″N 78°52′57″W (40.637259, -78.882627).
According to the United States Census Bureau, the CDP has a total area of 3.8 square miles (9.8 km2), all of it land.
At the 2000 census there were 786 people, 304 households, and 221 families in the CDP. The population density was 204.0 people per square mile (78.8/km2). There were 326 housing units at an average density of 84.6/sq mi (32.7/km2). The racial makeup of the CDP was 99.49% White, 0.25% African American, 0.13% Native American, and 0.13% from two or more races. Hispanic or Latino of any race were 0.13%.
There were 304 households, 32.9% had children under the age of 18 living with them, 56.3% were married couples living together, 11.8% had a female householder with no husband present, and 27.0% were non-families. 26.0% of households were made up of individuals, and 16.1% were one person aged 65 or older. The average household size was 2.59 and the average family size was 3.09.
The age distribution was 24.8% under the age of 18, 9.2% from 18 to 24, 26.1% from 25 to 44, 21.9% from 45 to 64, and 18.1% 65 or older.