From the record
“The Regency Bridge, locally known as the "Swinging Bridge," is a one-lane suspension bridge over the Colorado River in Texas. It is located at the intersection of Mills County Road 433 and San Saba County Road 137, both gravel roads, near a small community called Regency.”
Wikipedia article Regency Bridge, CC BY-SA 4.0.
One of 3 National Register listings published here for Mills County · listed in 1976 · category: Structure · built in 1939.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service