Avon-by-the-Sea is a quaint, seaside Victorian community located on the Atlantic Ocean in Monmouth County, New Jersey. As of the 2010 United States Census, the borough population was 1,901. Although many of the vacationers and locals call it Avon, the correct pronunciation is Ah-von (not Ay-von).

As of the census of 2000, there were 2,244 people, 1,043 households, and 535 families residing in the borough. The population density was 5,262.9 people per square mile (2,014.9/km2). There were 1,387 housing units at an average density of 3,253.0 per square mile (1,245.4/km2). The racial makeup of the borough was 97.15% White, 0.53% African American, 0.45% Native American, 0.89% Asian, 0.62% from other races, and 0.36% from two or more races. Hispanic or Latino of any race were 2.41% of the population.

As of the 2000 census, 36.5% of Avon-by-the-Sea residents were of Irish ancestry, the third-highest percentage of any municipality in the United States, and second-highest in New Jersey, among all places with more than 1,000 residents identifying their ancestry.

There were 1,043 households out of which 18.6% had children under the age of 18 living with them, 42.8% were married couples living together, 6.4% had a female householder with no husband present, and 48.7% were non-families. 41.1% of all households were made up of individuals and 18.5% had someone living alone who was 65 years of age or older. The average household size was 2.15 and the average family size was 3.04.

In the borough the population was spread out with 18.4% under the age of 18, 4.8% from 18 to 24, 28.7% from 25 to 44, 25.8% from 45 to 64, and 22.3% who were 65 years of age or older. The median age was 44 years. For every 100 females there were 93.4 males. For every 100 females age 18 and over, there were 87.4 males.

The median income for a household in the borough was $60,192, and the median income for a family was $80,605. Males had a median income of $53,125 versus $35,857 for females. The per capita income for the borough was $41,238. About 2.3% of families and 2.7% of the population were below the poverty line, including 3.0% of those under age 18 and 4.4% of those age 65 or over.