Sunbury is a city located in Northumberland County Pennsylvania. It is also the county seat of Northumberland County. With a 2020 population of 9,258, it is the 74th largest city in Pennsylvania and the 3264th largest city in the United States . Sunbury is currently declining at a rate of -0.56% annually and its population has decreased by -6.53% since the most recent census, which recorded a population of 9,905 in 2010. Sunbury reached it's highest population of in . Spanning over 2 miles, Sunbury has a population density of 4,577 people per square mile.
The average household income in Sunbury is $47,671 with a poverty rate of 18.93%. The median rental costs in recent years comes to $650 per month, and the median house value is $81,300. The median age in Sunbury is 35.7 years, 34.1 years for males, and 39.4 years for females.