The South Fork Bridge is a historic bridge spanning the South Fork Saline River in Fountain Lake, Arkansas. It formerly carried Arkansas Highway 128, whose modern bridge now stands just to the south, a short way east of its junction with Arkansas Highway 5. It is a two-span concrete closed-spandrel arch structure, with spans of and a roadway width of . It was built in 1928 by a county crew, after major flooding in 1927 damaged road infrastructure in the area.
The bridge was listed on the National Register of Historic Places in 1990.