Sag Bridge

Sag Bridge is a four-lane truss bridge carrying traffic across the Calumet Sag Channel. The structure uses a Pennsylvania through truss design, with steel framework visible from both sides of the waterway.

Built in 1934, the bridge was designed to connect Illinois Route 83 and Illinois Route 171 across the channel. This construction tied together growing transportation networks that served the industrial regions of Cook County.

The structure reflects how engineers solved transportation challenges in the 1930s industrial era. Visitors can observe the massive steel framework that shaped how people and goods moved through this industrial region.

The bridge is visible and accessible from the surrounding roads and paths near the Calumet Sag Channel. Daylight hours provide the clearest views of the steel structure and its engineering details.

The bridge sits at the point where two ancient waterways, the Sag Outlet and DesPlaines Outlet, merged into the Chicago Outlet River system. This spot marks a significant junction in the region's water management history.

Location: Lemont

GPS coordinates: 41.68830,-87.93310

Latest update: December 11, 2025 18:06