The Longest Wooden Bridge in the World Is a California Swimming Hole

Head northeast out of Marysville into the Sierra foothills and, if you know where to turn, the road drops you down to a bend in the South Yuba River where a 233-foot wooden barn appears to be lying across the water. That's the Bridgeport Covered Bridge, and despite sitting a long way from the New England back roads most people picture, it holds a record neither Vermont nor Pennsylvania can touch: the longest clear single span of any surviving wooden covered bridge on the planet.

Photo by BenFranske (CC BY-SA 3.0, via Wikimedia Commons)

A toll road to the silver mines

The bridge was never meant to be a landmark. In 1862 it was a business expense. A millwright named David Wood built it for the Virginia Turnpike Company as one link in a 14-mile toll road, and the whole operation existed to move freight toward the silver strike of the Comstock Lode, discovered across the Nevada line in 1859.

The supply chain behind it was genuinely improbable. Goods came up from San Francisco Bay by steamboat, chugging up the Sacramento River to Marysville, where they were transferred onto wagons for the long grind over the Sierra Nevada by way of the Virginia Turnpike and Henness Pass Road. The Bridgeport bridge was the pinch point where all that traffic crossed the Yuba. Wood cut the lumber at his own sawmill up in Sierra County and hauled it down, which tells you something about how much this crossing was worth to him.

Using it wasn't free, obviously. A foot traveler paid a quarter, a man on horseback paid fifty cents, and a teamster driving eight animals paid six dollars — the maximum toll, and a real amount of money in 1862. The company recouped its investment one wagon at a time.

How you build a 200-foot wooden span that lasts

The engineering is the part that still impresses. Wood combined a Howe truss — a timber frame stiffened with iron tension rods, patented in the 1840s — with an auxiliary Burr arch, a laminated wooden arch running the length of the span to carry extra load. The arches were built up from Douglas fir and anchored at each end in massive granite blocks, and you can see them from inside the bridge and out, which is half the fun of visiting.

Then he wrapped the whole thing. More than 27,000 sugar-pine shingles clad the roof and sides, and that siding is the entire point of a covered bridge: it keeps the working timbers dry. An exposed wooden truss rots at the joints within a couple of decades. Sheltered, the same frame can stand for a century and a half — which this one has, and then some.

The clear span runs a little over 208 feet between supports. For years the title of longest single-span covered bridge was disputed with New York's Old Blenheim Bridge, a rivalry that ended in the grimmest way possible when floodwaters from Hurricane Irene tore Blenheim off its abutments in 2011. Bridgeport has been the undisputed record-holder ever since, which is not the kind of record you want to win by default.

Closed, nearly lost, and hauled back

The bridge outlived its own reason for existing fairly quickly. When the transcontinental railroad reached Reno in 1868, most of the Comstock freight abandoned the wagon roads overnight, and Bridgeport settled into a quiet second life serving local foothill traffic. Cars crossed it until 1972. Pedestrians until 2011, when inspectors closed it outright over structural problems — a polite way of saying the 150-year-old timbers were no longer to be trusted.

For a while it looked like the story might end there. Then, in 2014, Governor Jerry Brown signed a budget with $1.3 million earmarked for the bridge, the first real money toward saving it. The full rehabilitation eventually ran to roughly $6.9 million. Crews jacked the span up on temporary supports, rebuilt the main top chord, swapped out failed timbers and tension rods, rebuilt the stone abutments, and re-shingled the whole exterior. It reopened to foot traffic in November 2021.

You'll find it today as the centerpiece of South Yuba River State Park, listed on the National Register of Historic Places since 1971 and marked as California Historical Landmark No. 390. On a hot afternoon the pools beneath it fill with swimmers who mostly have no idea they're paddling under a world record. Go stand inside it instead, look up at that long fir arch, and consider that a mill owner chasing silver-mine freight accidentally built the thing everyone else has been trying to beat ever since.

Images via Wikimedia Commons. Header and interior photo by BenFranske (CC BY-SA 3.0); thumbnail by Rick Cooper (CC BY 2.0).