Rockbridge in Richland County, Wisconsin
Photo by Jay Wilbur
NABSQNO 15T-713240-4813850. Rockbridge is a very unusual structure and is probably best classified as an irregular natural arch. Vreeland classified it as a meander natural bridge, most likely because Pine River flows through the opening. However, it is unlikely that the river had much to do with the formation of the opening. It is much more likely that the obvious enlarged vertical joint formed prior to the time the meandering river found the opening, probably just by coincidence. Furthermore, wall collapse was not a factor in the arch's origin. Nevertheless, Rockbridge is a true natural arch and not merely an enlarged crack.
Rockbridge is located in Pier County Park in Rockbridge Township, Richland County, Wisconsin. The Vreeland catalog number for this arch is 14-16. Vreeland reported a span of 20 feet.