The Pengra Bridge contains two of the longest timbers ever cut for a bridge in Oregon. The lower chords measuring 16` x 18` x 126 feet were too large to be ran through a mill and were therefore rough hewn in the woods. Booth-Kelley Lumber Company cut and transported the timbers to the bridge site by truck where they were resurfaced before being set into place
The bridge was named for B.J. Pengra, a pioneer who eventually became general Surveyor of Oregon in 1862. Pengra surveyed the Oregon Central Military Road which linked the Willamette Valley with the Owyhee mining country of Eastern Oregon Cross Dexter Reservoir and drive north