Nestled in the middle of the Susquehanna River Valley in Central Pennsylvania, Selinsgrove is located along US Route 11 & US Route 15, 50 miles (80 km) north of Harrisburg and about five miles (8 km) southwest of Sunbury. Routes 11 & 15 once traversed the borough by its primary artery, Market Street. Traffic concerns led to the construction of a bypass to funnel long haul traffic around the historic downtown. Like many similar projects, an unintended consequence of this bypass was the growth of retail and commercial businesses in the communities north of the borough. Selinsgrove's downtown has sought to reinvent itself by emphasizing its historic charm.
The Dauntless Hook & Ladder volunteer fire company provides emergency services to the borough's residents.
As of the census of 2000, there were 5,383 people, 1,767 households, and 987 families residing in the borough. The population density was 2,790.3 people per square mile (1,076.9/km²). There were 1,912 housing units at an average density of 991.1/sq mi (382.5/km²). The racial makeup of the borough was 94.67% White, 2.73% African American, 0.07% Native American, 0.91% Asian, 0.87% from other races, and 0.74% from two or more races. Hispanic or Latino of any race were 2.92% of the population.
There were 1,767 households out of which 23.5% had children under the age of 18 living with them, 40.5% were married couples living together, 12.3% had a female householder with no husband present, and 44.1% were non-families. 34.2% of all households were made up of individuals and 14.7% had someone living alone who was 65 years of age or older. The average household size was 2.18 and the average family size was 2.75.
In the borough, the population was spread out with 14.6% under the age of 18, 34.9% from 18 to 24, 18.7% from 25 to 44, 15.0% from 45 to 64, and 16.7% who were 65 years of age or older. The median age was 26 years. For every 100 females there were 77.9 males. For every 100 females age 18 and over, there were 74.7 males.
The median income for a household in the borough was $31,034, and the median income for a family was $42,500. Males had a median income of $29,679 versus $22,115 for females. The per capita income for the borough was $13,401. About 7.8% of families and 16.7% of the population were below the poverty line, including 13.8% of those under age 18 and 10.4% of those age 65 or over.
The average weekly wage for Snyder County in 2005 was $553. This is equivalent to $13.83 per hour or $28,756 per year, assuming a 40-hour week worked the year around. Center for Workforce Information and Analysis.