(from http://news.mcdonalds.com)

McDonald’s USA will be giving away 10,000 limited edition bottles of beloved Big Mac Special Sauce on January 26 at participating restaurants nationwide. Customers can find Big Mac Special Sauce bottles in their market by downloading the Big Mac Special Sauce Finder iMessage app that highlights the nearest restaurant where the limited edition bottles will be available.* (MORE HERE)

Here are the locations in Illinois

1313 N State St, Belvidere, IL 61008-2002
4623 State St, Rockford, IL 61108-2118
4403 Harrison Ave, Rockford, IL 61108-7927
616 E Green St, Champaign, IL 61820
627 N Western Ave, Peoria, IL 61604
1156 Vaughn Rd., Wood River, IL 62905