The Population & Steets in Gowin City are listed below. You can use this information to learn more about the city. This area is located in Northumberland County, Pennsylvania. The ZIP code for Gowen City is 48384. The ZIP code is an area code that can be used for mailing purposes. Some ZIP codes have alternative names that are often used for large neighborhoods or sections of a city. Some ZIP codes have several "acceptable" names that group different towns together. You can use either a five-digit or a detailed nine-digit zipcode for your mailing needs.