Lewis & Clark Memorial Bridge
I-90 Missouri River Highway Crossing
Chamberlain, SD

Lewis & Clark Memorial Bridge

• Structure ID: NBI 000000008061094
• Location: River Mile ???
• River Elevation: 1,354 Feet
• Highway: Interstate I-90
• Daily Traffic Count: 7,520 (2006)
• Bridge Type: Steel Girder, Concrete Deck
• Length: 2,031 Feet
• Width: 78 Feet, 4 Lanes
• Navigation Channel Width: Non-Navigable
• Height Above Water: 33 Feet
• Date Built: Dedicated July 7, 1974
Each state along the Missouri River has its Lewis & Clark Bridge. This bridge is the South Dakota version. The Lewis & Clark Expedition stopped at Chamberlain near the future location of this bridge. The spent several days in the area drying out their supplies and repacking their boats. Lewis wrote that they dines on acorns and plumbs along with buffalo and magpie. This is the first that they had eaten magpie since the bridge is not known in the eastern part of the country. There is a very nice Lewis & Clark Interpretive Center located at the rest stop on I-90 just east of the bridge.

The Lewis & Clark Memorial Bridge was built for the Interstate Highway program. I-90 was built though South Dakota in the early 1970s. The US-16 bridge was considered for the river crossing, but was soon rejected because it would have required running I-90 through the city of Chamberlain. A new bridge was needed on a new alignment. The result was the current 2,031 foot long structure with an equally long causeway on the west side of the crossing, for a total project length of nearly a mile.

The bridge is a very economical steel girder structure. It was built for minimal cost, which explains why it has no decorative features. Had the bridge been built today, it would have been built with modern guardrails, a larger divider in the middle, wider lanes, full width shoulders, and more distance between the two sets of lanes. While that might have been ideal, the current bridge is in good condition, and simply doesn't warrant the cost of replacement.


Lewis & Clark Memorial Bridge
Lewis & Clark Memorial Bridge
Lewis & Clark Memorial Bridge
Lewis & Clark Memorial Bridge
Lewis & Clark Memorial Bridge
Lewis & Clark Memorial Bridge
Lewis & Clark Memorial Bridge

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Photo and text by John A. Weeks III, Copyright © 2008, all rights reserved.
For further information, contact: john@johnweeks.com