The United State Federal Highway Administration (FHWA) collects and updates information on the nation's bridges that are located on public roads, including both interstate and US highways, state and county roads, and publicly accessible bridges on federal land.  This collection of information is known as the National Bridge Inventory (NBI), and it has been captured electronically since 1972.  While parts of the data were first made available to the public in 1997, it wasn't until 2007 that the FWHA decided to make all elements of the NBI database publicly available.

This NBI data set contains 135 variables describing over 600,000 bridges.  Variables describe the location, structure, maintenance, usage, status, and other aspects of the bridges.  An extremely detailed (124 page) pdf guide to the variables, codes, and other metadata on the NBI can be found here:

https://www.fhwa.dot.gov/bridge/mtguide.pdf

Acknowledgements

The Department of Transportation FHWA collects and provides the NBI data as authorized by statue 23, U.S.C. 151

This data set was downloaded from the Homeland Infrastructure Foundation here:

https://hifld-dhs-gii.opendata.arcgis.com/datasets/94c41e96db0d4b85b9eb622923e0a0e8_0