Area Code Lookup
What Area Code Is Oswego?
Area code 331 · Illinois
Oswego uses area code 331. It is located in Illinois.
Area Code Serving Oswego
Frequently Asked Questions
What area code is Oswego?
Oswego uses area code 331. It is located in Illinois.
How do I call Oswego from outside the US?
To call Oswego from abroad, dial +1 followed by the area code and 7-digit local number (e.g. +1-331-XXX-XXXX). The +1 is the country code for all NANPA countries.