What is now Eatontown was originally incorporated as Eatontown Township by an Act of the New Jersey Legislature on April 4, 1873, from portions of Ocean Township and Shrewsbury Township. Portions of the township were taken to form West Long Branch (April 7, 1908) and Oceanport (April 6, 1920). Eatontown was reincorporated as a borough on March 8, 1926, replacing Eatontown Township, based on the results of a referendum held on April 13, 1926.
The United States Army's Fort Monmouth has been in Eatontown since 1917, and is home to the U.S. Army Materiel Command's (AMC) Communication and Electronics Command (CECOM). Fort Monmouth is also home to the United States Military Academy Preparatory School (or USMAPS), which trains approximately 250 students per year to enter as freshmen (plebes) at the United States Military Academy at West Point.
In the center of Eatontown is the Monmouth Mall, located at the intersection of Route 35 and Route 36. Monmouth Mall has a variety of stores, restaurants, and a 15-screen cineplex.
As of the census of 2000, there were 14,008 people, 5,780 households, and 3,444 families residing in the borough. The population density was 2,366.8 people per square mile (913.6/km²). There were 6,341 housing units at an average density of 1,071.4/sq mi (413.6/km²). The racial makeup of the borough was 73.29% White, 11.61% African American, 0.34% Native American, 9.32% Asian, 0.04% Pacific Islander, 2.31% from other races, and 3.10% from two or more races. Hispanic or Latino of any race were 6.62% of the population.
There were 5,780 households out of which 28.7% had children under the age of 18 living with them, 46.8% were married couples living together, 9.9% had a female householder with no husband present, and 40.4% were non-families. 33.8% of all households were made up of individuals and 10.0% had someone living alone who was 65 years of age or older. The average household size was 2.35 and the average family size was 3.08.
In the borough the population was spread out with 22.9% under the age of 18, 7.0% from 18 to 24, 35.0% from 25 to 44, 21.7% from 45 to 64, and 13.3% who were 65 years of age or older. The median age was 37 years. For every 100 females there were 94.7 males. For every 100 females age 18 and over, there were 91.2 males.
The median income for a household in the borough was $53,833, and the median income for a family was $69,397. Males had a median income of $49,508 versus $35,109 for females. The per capita income for the borough was $26,965. About 3.5% of families and 5.7% of the population were below the poverty line, including 4.3% of those under age 18 and 9.2% of those age 65 or over.