According to Forbes Magazine, Delaware County is the fifth best place in the United States to raise a family and the best place in the state of Ohio to reside. It was home to former U.S. President Rutherford B. Hayes.
As of the census of 2000, there were 109,989 people, 39,674 households, and 30,668 families residing in the county. The population density is 249 people per square mile (96/km²). There were 42,374 housing units at an average density of 96 per square mile (37/km²). The racial makeup of the county was 94.25% White, 2.52% Black or African American, 0.14% Native American, 1.54% Asian, 0.03% Pacific Islander, 0.38% from other races, and 1.14% from two or more races. Hispanic or Latino of any race were 1.01% of the population. 26.8% were of German, 11.7% Irish, 11.3% English, 10.7% American and 6.9% Italian ancestry according to Census 2000.
There were 39,674 households out of which 40.10% had children under the age of 18 living with them, 67.70% were married couples living together, 6.70% had a female householder with no husband present, and 22.70% were non-families. 18.10% of all households were made up of individuals and 5.30% had someone living alone who was 65 years of age or older. The average household size was 2.70 and the average family size was 3.09.
In the county the population was spread out with 28.20% under the age of 18, 7.60% from 18 to 24, 32.60% from 25 to 44, 23.30% from 45 to 64, and 8.20% who were 65 years of age or older. The median age was 35 years. For every 100 females there were 98.00 males. For every 100 females age 18 and over, there were 94.90 males.
The median income for a household in the county was $67,258, and the median income for a family was $76,453. Males had a median income of $51,428 versus $33,041 for females. The per capita income for the county was $31,600. About 2.90% of families and 3.80% of the population were below the poverty line, including 4.40% of those under the age of 18 and 4.80% of those 65 and older.
By 2007, the median income for a household and for a family had risen to $80,526 and $94,099 respectively.
Interstate 71 and U.S. Highway 23 pass through the county. Interstate 71 crosses over Alum Creek immediately south of the Alum Creek Lake recreation area.
The area is served by the Delaware Municipal Airport, which is strategically located to serve the rapidly developing southern Delaware County area and the north portion of the Franklin County and Columbus, Ohio, areas. The airport contains a 5,000 foot runway, flight terminal, lounges, and weather briefing areas. It is home to approximately 80 aircraft and an estimated 40,000 operations take place per year. Several smaller airports are located in the county.