IAIS/Rock Island 1924 Bridge over Sylvan Slough near Rock Island

(Bridge Hunter, no Historic Bridges, John Weeks III, 3D Satellite, Street View)

Today's geography lesson, boys and girls, is that the channel between Arsenal Island and Rock Island is called the Sylvan Slough.

Dustin Oliver Flickr 2007 Photo, License: Creative Commons Attribution-NonCommercial (CC BY-NC)
Railroad bridge connecting the Rock Island Arsenal (Arsenal Island) with the city of Rock Island, Illinois across Sylvan Slough of the Mississippi River.

The Rock Island bridges (predecessors and current) across the main channel are famous because Rock Island built the first railroad bridge across the Mississippi River. What looks like just yet another pony plate girder bridge over the slough is historic because, at the time, the 90' girders were the largest (longest and heaviest) bridge girders in the world.

Bridge Hunter

David Sebben shared

Sylvan Slough Bridge Construction- August 25, 1923

On the afternoon of Saturday, August 25, 1923, the longest and heaviest steel bridge girder ever laid across a stream in America was lowered into position over Sylvan slough between the city of Moline and the Rock Island Arsenal.

Miles W. Rich that bridge is a long way from Moline, about 18 or 19 blocks. It spans the Sylvan Slough between Arsenal Island and the City of Rock Island.

[Another reminder that hard hats were not worn in the 1920s. Now days, even managers on a work site must wear them.]