As of the census of 2000, there were 6,920 people, 2,616 households, and 1,935 families residing in the town. The population density was . There were 2,846 housing units at an average density of . The racial makeup of the town was 97.66% White, 0.48% African American, 0.77% Native American, 0.46% Asian, 0.12% from other races, and 0.52% from two or more races. Hispanic or Latino of any race were 0.66% of the population.
There were 2,616 households, out of which 32.1% had children under the age of 18 living with them, 61.5% were married couples living together, 8.9% had a female householder with no husband present, and 26.0% were non-families. 21.5% of all households were made up of individuals, and 9.0% 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 3.04.
In the town, the population was spread out, with 24.6% under the age of 18, 7.3% from 18 to 24, 26.4% from 25 to 44, 27.2% from 45 to 64, and 14.6% who were 65 years of age or older. The median age was 40 years. For every 100 females, there were 98.2 males. For every 100 females age 18 and over, there were 93.7 males.
The median income for a household in the town was $50,425, and the median income for a family was $60,373. Males had a median income of $41,985 versus $27,027 for females. The per capita income for the town was $23,951. About 2.2% of families and 4.1% of the population were below the poverty line, including 4.5% of those under age 18 and 3.5% of those age 65 or over.
Communities and locations in Porter
- Blairville – A hamlet southeast of Youngstown on Creek Road (Route 18).
- Fillmore Chapel – A hamlet in the northeast corner of the town.
- Fort Niagara – A historic colonial fortification in Fort Niagara State Park.
- Fort Niagara State Park – A park at the mouth of the Niagara River.
- Four Mile Creek – A stream that flows northward through the west side of the town and enters Lake Ontario at the state park.
- Four Mile Creek State Park – A lakeside park on the shore of Lake Ontario.
- Porter Center – A hamlet centrally located in the town on the Youngstown-Lockport Road (Route 93).
- Old Fort Niagara State Historic Site – An official New York historic site that includes Fort Niagara.
- Ransomville – A hamlet in the southeast corner of the town on Route 93.
- Ransomville Speedway – A racetrack located northwest of Ransomville.
- Towers Corners – A hamlet by the intersection of Creek Road (Route 18) and the Youngstown-Lockport Road (Route 93), in the northeast part of the town.
- Youngstown – The Village of Youngstown is at the town's western border.