|o Total||1.2 sq mi (3.0 km2)|
|o Land||1.2 sq mi (3.0 km2)|
|o Density||580/sq mi (220/km2)|
|Time zone||Eastern (EST) (UTC-5)|
|o Summer (DST)||EDT (UTC-4)|
According to the United States Census Bureau, the CDP has a total area of 1.1 square miles (2.8 km2), all of it land.
As of the census of 2000, there were 668 people, 221 households, and 165 families residing in the CDP. The population density was 580.4 people per square mile (224.3/km²). There were 231 housing units at an average density of 200.7/sq mi (77.6/km²). The racial makeup of the CDP was 97.31% White, 1.20% African American, 0.60% Native American, 0.15% Pacific Islander, 0.45% from other races, and 0.30% from two or more races. Hispanic or Latino of any race were 1.05% of the population.
There were 221 households out of which 38.0% had children under the age of 18 living with them, 60.2% were married couples living together, 10.4% had a female householder with no husband present, and 25.3% were non-families. 22.6% of all households were made up of individuals and 7.7% had someone living alone who was 65 years of age or older. The average household size was 2.76 and the average family size was 3.24.
In the CDP, the population was spread out with 27.5% under the age of 18, 17.1% from 18 to 24, 25.9% from 25 to 44, 21.1% from 45 to 64, and 8.4% who were 65 years of age or older. The median age was 31 years. For every 100 females, there were 89.8 males. For every 100 females age 18 and over, there were 87.6 males.
The median income for a household in the CDP was $28,500, and the median income for a family was $38,036. Males had a median income of $26,667 versus $18,971 for females. The per capita income for the CDP was $11,029. About 14.1% of families and 16.3% of the population were below the poverty line, including 23.5% of those under age 18 and 6.3% of those age 65 or over.
The community was founded in 1806 by Lt. Col. George Weirick (1773-1838), a veteran of the War of 1812, and son or Capt. Wilhelm Weirick (1731-1807), a veteran of the American Revolution, and grandson of German immigrant Johann Georg Weyrich (1702-1751). The village was originally called Weirickstown. Weirick served as county commissioner in 1824, justice of the peace in 1813, and as a member of the General Assembly of Pennsylvania (1832-1833). He is buried in the Salem Church Cemetery in Snyder County. The village name was later changed to Centreville, and then changed again due to a conflict with another village of the same name in Crawford County, PA. The nearby creek's name was adopted sometime after 1842. It was originally part of Northumberland County, then Union. On March 2, 1855, Penns Creek became part of Snyder County. Snyder County was named for Governor Simon Snyder of Selinsgrove. Buried in the old Sharon Lutheran Churchyard in Selinsgrove, Snyder was very popular and was the only governor of Pennsylvania to serve three terms.
Ongoing pollution and soil erosion in the region continue to degrade the water quality and the environment locally as well as regionally. Farming, wastewater treatment facilities and industrial spills are cited as contributing factors to loss of water quality. It also contributes to the pollution of the Chesapeake Bay. Controlling the wastewater discharges alone is expected to cost local taxpayers billions of dollars.
The Lower Penns Creek Watershed Association's central purpose is to protect, conserve, and improve the Lower Penns Creek watershed by promoting the wise stewardship of the land and aquatic resources. The organization is open to all citizens. The organization has sponsored a main stream assessment The Lower Penns Creek watershed is approximately 163 square miles (420 km2) within Snyder and Union Counties. It drains into the Susquehanna River on the northern border of the community of Selinsgrove, Pennsylvania. It is located within the Lower Susquehanna subbasin. LPCWA's efforts contribute to the success of the missions of the Susquehanna Greenway Partnership and the Susquehanna River Basin Commission. The Snyder County Conservation District and the Union County Conservation District both have watershed specialists that participate in LPCWA.