Source: Historic Bridge Context for South Dakota
BH Photo #268415
At first I thought a pin-connected Warren truss in this county was the Thacher truss referred to in HAER documention. However, I finally found mention of this actual Thacher truss in Hamlin County. However, I am not 100% sure where it was located. Its probably demolished. Because of its name, I assume it was near Castlewood, and it was reported to cross Big Sioux River. The map points to my "Best Guess" for the bridge... I can see remains of caissons in the imagry.