The Sangamon County Treasurer's Office is responsible for maintaining vendor information and paying vendors via check or ACH. Sangamon County requires all vendors to complete and send to us a W-9 before payments are made to a vendor. In addition to the W-9, Sangamon County prefers to pay vendors via ACH whenever possible to reduce the cost of payment. Vendors should also complete a Vendor ACH form to sign up for this payment method. The vendor forms are available below. Vendors may e-mail completed forms to TRSFINREQ@Co.sangamon.il.us or fax them to 217-753-6837 or mail them to Sangamon County Treasurer's Office, 200 S. Ninth St, Room 102, Springfield, IL 62701.