The World's Longest Bridge Over Water: Danyang–Kunshan Grand Bridge, China

The Danyang–Kunshan Grand Bridge on the Beijing–Shanghai High-Speed Railway holds the Guinness World Record for the longest bridge over water (and longest bridge overall).

Vital Statistics

• Length: 164.8 km (102.4 miles)
• Completed: 2010; opened June 30, 2011
• Location: Jiangsu Province, China — spans the Yangtze River Delta from Danyang to Kunshan
• Structure: Elevated viaduct (precast box girders on pile foundations)
• Use: High-speed rail only (CRH380A/AL, 300–350 km/h)
• Cost: ~$8.5 billion (part of $32B Beijing–Shanghai HSR)

Engineering Context

The bridge crosses a maze of rivers, canals, lakes (including Yangcheng Lake), rice paddies, and soft alluvial soils. Rather than tunneling or filling, engineers chose a continuous viaduct—minimizing land acquisition, environmental disruption, and settlement risk. Average span: 80 m. Piles driven 60–80 m into soft clay.

Notable "Over Water" Distinctions

• Longest over water (total): Danyang–Kunshan (164.8 km) — but much crosses wetlands/floodplain, not open water.
• Longest continuous over open water: Hong Kong–Zhuhai–Macau Bridge (HZMB) — 29.6 km main bridge + 6.7 km tunnel + artificial islands = 55 km link. Longest sea-crossing.
• Longest over water (single span): Akashi Kaikyō Bridge (Japan) — 1,991 m central span (suspension).
• Longest U.S. over water: Lake Pontchartrain Causeway (Louisiana) — 38.4 km (23.9 mi) continuous over lake.

Why It Matters

Danyang–Kunshan isn't a showcase span—it's industrial infrastructure at planetary scale. It carries 200M+ passengers/year, cut Beijing–Shanghai from 10 hrs to 4.5 hrs. It represents China's high-speed rail network: 42,000+ km (2023), ¾ of world's total. The bridge is the network's longest single element—a viaduct that stitches the Yangtze Delta's cities into a mega-region.

Longest bridge over water. Not the most beautiful. But the one that moves the most people, fastest, across the most complex terrain.