At the 2000 census, there were 4,983 people, 1,661 households and 1,333 families residing in the township. The population density was . There were 2,967 housing units at an average density of . The racial makeup of the township was 86.49% White, 7.06% African American, 0.24% Native American, 0.94% Asian, 0.02% Pacific Islander, 2.39% from other races, and 2.85% from two or more races. Hispanic or Latino of any race were 9.47% of the population.
There were 1,661 households, of which 41.9% had children under the age of 18 living with them, 67.9% were married couples living together, 7.8% had a female householder with no husband present, and 19.7% were non-families. 15.4% of all households were made up of individuals, and 4.6% had someone living alone who was 65 years of age or older. The average household size was 3.00 and the average family size was 3.35.
31.5% of the population were under the age of 18, 6.2% from 18 to 24, 31.5% from 25 to 44, 21.4% from 45 to 64, and 9.4% who were 65 years of age or older. The median age was 36 years. For every 100 females, there were 103.0 males. For every 100 females age 18 and over, there were 100.1 males.
The median household income was $42,448 and the median family income was $46,996. Males had a median income of $38,669 compared with $23,986 for females. The per capita income for the township was $15,927. About 10.3% of families and 13.5% of the population were below the poverty line, including 18.6% of those under age 18 and 8.5% of those age 65 or over.
<!-- PresRow should be -->
|}
Climate
According to the Trewartha climate classification system, Tunkhannock Township has a Temperate Continental climate (Dc) with warm summers (b), cold winters (o) and year-around precipitation (Dcbo). Dcbo climates are characterized by at least one month having an average mean temperature ≤ , four to seven months with an average mean temperature ≥ , all months with an average mean temperature < and no significant precipitation difference between seasons. Although most summer days are comfortably humid in Tunkhannock Township, episodes of heat and high humidity can occur, with heat index values > . Since 1981, the highest air temperature has been July 22, 2011, and the highest daily average mean dew point was on August 1, 2006. July is the peak month for thunderstorm activity, which correlates with the average warmest month of the year. Since 1981, the wettest calendar day has been on September 30, 2010. During the winter months, the plant hardiness zone is 5b with an average annual extreme minimum air temperature of . Since 1981, the coldest air temperature has been on January 21, 1994. Episodes of extreme cold and wind can occur with wind chill values < . The average snowiest month is January which correlates with the average coldest month of the year. Ice storms and large snowstorms depositing ≥ of snow occur nearly every year, particularly during nor’easters from December through March.
Transportation
As of 2020, there were of public roads in Tunkhannock Township, of which were maintained by the Pennsylvania Department of Transportation (PennDOT) and were maintained by the township.
Interstate 80 is the most prominent highway traversing Tunkhannock Township. It follows an east-west alignment across the northern portion of the township, including part of the interchange with Interstate 380, but the nearest interchanges with local roads are in neighboring townships. Pennsylvania Route 115 is the main numbered highway providing direct local access to the township. It follows a southeast-northwest alignment across southern and western parts of the township. Pennsylvania Route 903 begins at PA 115 in the western corner of the township and heads southwestward out of the township.
Ecology
According to the A. W. Kuchler U.S. potential natural vegetation types, Tunkhannock Township would have a dominant vegetation type of Northern Hardwood (106) with a dominant vegetation form of Northern hardwood forest (26). The peak spring bloom typically occurs in early-May and peak fall color usually occurs in early-October. The plant hardiness zone is 5b with an average annual extreme minimum air temperature of .