According to the United States Census Bureau, the CDP has a total area of 3.5 square miles (9.1 km2), of which 1.5 square miles (3.8 km2) is land and 2.1 square miles (5.4 km2), or 58.64%, is water.
Located on Long Island Sound, Niantic Bay is popular for swimming, fishing and boating. Wednesday evenings and Sunday afternoons, the Niantic Bay Yacht Club organizes sailboat races and the Bay is filled with sailboats. The Millstone Nuclear Power Plant in nearby Waterford is visible on the bay's eastern horizon line.
Beachgoers may want to seek out the local Rocky Neck State Park, whose mile of beach offers much better views of Long Island Sound, including several offshore islands such as Gardiners Island, Plum Island, and Orient Point, the distant tip of Long Island.
The Rocky Neck beach is known for its sandbar, one of the few places along the Connecticut shoreline free of rocks and stones. At low tide the sandbar lies exposed and bathers may walk out into the water for quite some distance before reaching waist-deep water. The sandbar at low tide is a popular place with kids for building sandcastles, digging holes and flinging mud. Besides beachgoing, Rocky Neck also offers camping in the summertime and a large, flat meadow area also has a number of picnic tables and outdoor barbecue grills. Weekends are usually the most crowded time in summer, with many people coming down to the shore to get away from the more intense inland heat.
In the off-season, Rocky Neck is popular with locals for hikes through the woods (the wooded areas of Rocky Neck feature some great hiking trails, but make sure to avoid them in the summer heat when the deer flies, whose bite is nasty, make hiking less than a pleasure). Spring and fall are beautiful times for hiking and enjoying the quieter side of Rocky Neck. On mild winter days one will find local inhabitants enjoying a stroll along the beach.
Once famous for its Niantic River scallops, the scallop population has been in decline for a number of years. Attempts to revive the scallop population have not met with much success, most likely due to increased pollution from the heavy traffic of motorboats on the river. Nonetheless, boating, fishing and swimming are all popular summer activities up and down the river.
As of the census of 2000, there were 3,085 people, 1,404 households, and 835 families residing in the CDP. The population density was 2,110.3 people per square mile (815.8/km2). There were 1,756 housing units at an average density of 1,201.2 per square mile (464.4/km2). The racial makeup of the CDP was 96.63% White, 0.49% African American, 0.16% Native American, 1.23% Asian, 0.42% from other races, and 1.07% from two or more races. Hispanic or Latino of any race were 2.11% of the population.
There were 1,404 households out of which 24.6% had children under the age of 18 living with them, 46.3% were married couples living together, 10.5% had a female householder with no husband present, and 40.5% were non-families. 33.4% of all households were made up of individuals and 11.7% had someone living alone who was 65 years of age or older. The average household size was 2.20 and the average family size was 2.81.
In the CDP the population was spread out with 20.3% under the age of 18, 5.9% from 18 to 24, 29.0% from 25 to 44, 27.0% from 45 to 64, and 17.8% who were 65 years of age or older. The median age was 42 years. For every 100 females there were 91.3 males. For every 100 females age 18 and over, there were 89.7 males.
The median income for a household in the CDP was $54,872, and the median income for a family was $65,077. Males had a median income of $46,887 versus $35,811 for females. The per capita income for the CDP was $27,306. About 1.9% of families and 3.6% of the population were below the poverty line, including 7.2% of those under age 18 and 1.8% of those age 65 or over.
According to www.city-data.com, the median income for a household in 2008 was $74,348, higher than the median income for the entire state of Connecticut ($68,595 in 2008). The median of all housing units in Niantic was $337,612 in 2008.
- William Colepaugh (1918–2005), Nazi sympathizer who grew up on Black Point and traveled to Germany in 1944 to be trained as a spy
- Tom Danielson (1978-) professional road bicycle racer
- Rajai Davis (1980-), baseball player for the Toronto Blue Jays
- Charles Drake (real name "Charles Ruppert") (1917–1994), actor in over 80 films and numerous television shows
- Otto Graham (1921–2003), Hall of Fame professional football player
- John McDonald, Major League Baseball player with the Arizona Diamondbacks
- Jeremy Powers, professional racing cyclist riding for Jelly Belly (cycling team)
- Jay Allen Sanford, author and cartoonist best known as the co-creator of the comic book Rock 'N' Roll Comics, and for his work with Revolutionary Comics, Carnal Comics, and the San Diego Reader
- William Nathan Harrell Smith (1812–1889), congressman from North Carolina; attended schools in East Lyme
- Ed Toth, professional musician currently with The Doobie Brothers, formerly with Vertical Horizon and Jennifer Culture
- Vladimir Peter Tytla (1904–1968), known as Bill Tytla, one of the original Disney animators
- Pete Walker, professional baseball player with several teams; currently a Toronto Blue Jays coach
- "Profile of General Population and Housing Characteristics: 2010 Demographic Profile Data (DP-1): Niantic CDP, Connecticut". U.S. Census Bureau, American Factfinder. Retrieved October 29, 2012.
- "American FactFinder". United States Census Bureau. Retrieved 2008-01-31.