According to Jeffrey M. Dorwart, Rio Grande was founded in the mid-nineteenth century around a country store owned by the Hildreth family. The community was originally called Hildreth for that reason. George F. Boyer and J. Pearson Cunningham explain that, during the colonial period, Aaron Leaming, the Hildreths and the Cresses had plantations in that area. Where the King's Highway crossed the road coming from Dennisville and Goshen a stage coach terminal was set up, and the spot became the center for trade for the local farming families. Boyer and Cunningham say that the area was known as "Leamings," for the prominent landholders, or as "Hildreth," the family who ran the local store. They continue, "The name, Rio Grande, was suggested by the seventh Aaron Leaming who thought this southern United States river had an attractive sound."
Geography
According to the United States Census Bureau, the CDP had a total area of 2.490 square miles, including 2.459 square miles of land and 0.031 square miles of water.
As of the 2000 United States Census there were 2,444 people, 1,029 households, and 658 families living in the CDP. The population density was 399.8/km2. There were 1,294 housing units at an average density of 211.7/km2. The racial makeup of the CDP was 90.79% White, 4.50% African American, 0.29% Native American, 0.94% Asian, 1.10% from other races, and 2.37% from two or more races. Hispanic or Latino of any race were 3.03% of the population. There were 1,029 households, out of which 25.5% had children under the age of 18 living with them; 46.6% were married couples living together; 13.6% had a female householder with no husband present; and 36.0% were non-families. 30.1% of all households were made up of individuals and 15.4% had someone living alone who was 65 years of age or older. The average household size was 2.36 and the average family size was 2.93. In the CDP the population was spread out with 21.6% under the age of 18, 7.7% from 18 to 24, 26.7% from 25 to 44, 24.1% from 45 to 64, and 19.9% who were 65 years of age or older. The median age was 42 years. For every 100 females, there were 91.7 males. For every 100 females age 18 and over, there were 91.8 males. The median income for a household in the CDP was $28,424, and the median income for a family was $38,007. Males had a median income of $32,935 versus $19,643 for females. The per capita income for the CDP was $18,792. About 20.9% of families and 21.4% of the population were below the poverty line, including 32.5% of those under age 18 and 17.9% of those age 65 or over.
Rio Grande is situated at the junction of U.S. Route 9 and Route 47. U.S. Route 9 runs south to Cape May and north toward the Atlantic City area while Route 47 runs southeast to Wildwood and north to Millville and the Camden area. Rio Grande is accessible from the Garden State Parkway at exit 4 northbound and exit 4B southbound. NJ Transit offers bus service from Rio Grande to Cape May and Philadelphia on the 313, 315 and 316 routes, to Cape May and the Port Authority Bus Terminal in Midtown Manhattan on the 319 route, to Wildwood on the 510 route, and to Cape May and Atlantic City on the 552 route. The Great American Trolley Company operates trolley service from North Wildwood and Wildwood to shopping centers in Rio Grande on Mondays through Fridays in the summer months. Cape May Airport, established in 1941 as NAS Rio Grande, is located in the area, in adjacent Lower Township.