National Park was formed as a borough by an Act of the New Jersey Legislature on April 15, 1902, from portions of West Deptford Township.
According to the United States Census Bureau, the borough has a total area of 1.4 square miles (3.7 km²), of which, 1.0 square miles (2.6 km²) of it is land and 0.4 square miles (1.1 km²) of it (30.56%) is water.
National Park borders West Deptford Township and the Delaware River.
The Delaware River shore faces the southern end of Philadelphia, approximately across from the mouth of the Schuylkill River and the site of Fort Mifflin.
There were 1,111 households out of which 37.3% had children under the age of 18 living with them, 58.2% were married couples living together, 14.0% had a female householder with no husband present, and 22.1% were non-families. 18.6% of all households were made up of individuals and 8.6% had someone living alone who was 65 years of age or older. The average household size was 2.86 and the average family size was 3.24.
In the borough the population was spread out with 26.4% under the age of 18, 9.3% from 18 to 24, 29.7% from 25 to 44, 22.2% from 45 to 64, and 12.5% who were 65 years of age or older. The median age was 37 years. For every 100 females there were 99.2 males. For every 100 females age 18 and over, there were 93.8 males.
The median income for a household in the borough was $48,534, and the median income for a family was $51,535. Males had a median income of $35,102 versus $27,398 for females. The per capita income for the borough was $18,048. About 6.5% of families and 7.6% of the population were below the poverty line, including 6.7% of those under age 18 and 7.9% of those age 65 or over.
The Mayor of National Park is Patricia M. Koloski. Members of the Borough Council Borough Council are Council President Dennis Mehaffey, Mark Cooper, Michael Duer, Anne Marie Henry, Harry Schaeffer and Michael Szatkowski.
For seventh through twelfth grade, public school students attend Gateway Regional High School, a regional public high school serving students from the boroughs of National Park, Wenonah, Westville and Woodbury Heights, as part of the Gateway Regional High School District.
On October 22 of that year, in what is known as the Battle of Red Bank, an attack by 900 Hessian troops, serving under British Major General William Howe, who then occupied Philadelphia, was repelled, with heavy losses on the Hessian side, including the death of their commander, Colonel Carl Emil Kurt von Donop, by the 600 Continental defenders under Colonel Christopher Greene. After the later loss of Fort Mifflin, Fort Mercer was abandoned without a fight when Lord Charles Cornwallis landed 2,000 British troops nearby on November 18.