Yardville is an unincorporated community and census-designated place (CDP) in Hamilton Township, Mercer County, New Jersey, United States. As of the 2020 United States census, the CDP's population was 6,965. Before the 2010 census, the area was part of the Yardville-Groveville CDP.

Yardville is in southern Mercer County, bordered to the northwest by White Horse and to the southeast by Groveville. It is bordered to the southwest by Crosswicks Creek, a tributary of the Delaware River, and by Burlington County across the creek. Interstate 195 forms part of the northern border of the CDP, while U.S. Route 130 runs through the center of the community, leading southwest 3 miles (5 km) to Bordentown and northeast 9 miles (14 km) to Hightstown. Trenton, the state capital, is 6 miles (10 km) northwest of Yardville.

According to the United States Census Bureau, the CDP has a total area of 4.10 square miles (10.62 km), including 4.07 square miles (10.54 km) of land and 0.03 square miles (0.08 km) of water (0.76%).

Historical population

Census	Pop.	Note	%±
2010	7,186		—
2020	6,965		−3.1%
U.S. Decennial Census

The 2010 United States census counted 7,186 people, 2,757 households, and 2,048 families in the CDP. The population density was 1,773.9 per square mile (684.9/km). There were 2,841 housing units at an average density of 701.3 per square mile (270.8/km). The racial makeup was 92.93% (6,678) White, 2.80% (201) Black or African American, 0.07% (5) Native American, 2.34% (168) Asian, 0.00% (0) Pacific Islander, 1.00% (72) from other races, and 0.86% (62) from two or more races. Hispanic or Latino of any race were 4.31% (310) of the population.

Of the 2,757 households, 28.4% had children under the age of 18; 61.2% were married couples living together; 9.0% had a female householder with no husband present and 25.7% were non-families. Of all households, 21.5% were made up of individuals and 9.3% had someone living alone who was 65 years of age or older. The average household size was 2.60 and the average family size was 3.03.

20.0% of the population were under the age of 18, 7.8% from 18 to 24, 23.5% from 25 to 44, 32.5% from 45 to 64, and 16.2% who were 65 years of age or older. The median age was 44.3 years. For every 100 females, the population had 96.5 males. For every 100 females ages 18 and older there were 91.6 males.

All of Hamilton Township, including Yardville, is served by the Hamilton Township School District.