Longest Bridges in America

America's longest bridges span miles of water, marshland, and urban landscapes. The Lake Pontchartrain Causeway in Louisiana stretches nearly 24 miles, while many interstate highway bridges cross wide river floodplains for thousands of feet. These structures represent some of the most significant engineering achievements in U.S. infrastructure.

Length alone doesn't determine a bridge's importance — a 100-foot bridge carrying 200,000 vehicles per day matters more to daily life than a mile-long rural span. But the longest bridges are often the most expensive to maintain and the hardest to replace when they deteriorate.

Longest Bridges by State