Where do I send Mastercard credit card payments? The mailing address is: P.O. Box 2711, Omaha, NE 68103-2711 Additionally, following the conversion, you will be able to make your payment through a transfer in Online Account Access or at any 3Rivers branch. Have more questions? Submit a request 0 Comments Article is closed for comments. Related articles How do I receive a PIN (Personal Identification Number) for my Mastercard credit card so I can access cash? Can I change the payment due date on my Mastercard credit card?