Longest free bridge in the US

[hotdogPi]

Since most very long bridges have tolls, I am wondering what the longest free bridge is.

It has to be free for cars in both directions.

[roadman65]

I would have to say either the Bridge to South Padre Island or the Hampton Roads Bridge Tunnel.

[Ga293]

It's the Manchac Swamp Bridge, on the the southern end of I-55 in Louisiana. In the US, only the Lake Pontchartrain Causeway is longer, and it's tolled.

[NE2]

It's the Manchac Swamp Bridge

Yup. bridges don't always cross major rivers.

[SteveG1988]

I'd also say if it is a bridge only over water, the Virginia Dare memorial bridge is 5.2 mi long and connects the outer banks to the mainland.

https://en.wikipedia.org/wiki/Virginia_Dare_Bridge

Slightly longer is the I-10 twin span: https://en.wikipedia.org/wiki/I-10_Twin_Span_Bridge

[froggie]

Technically speaking (and something we've had a thread about here in the past), one could start at the north end of the Manchac Swamp Bridge and go south on I-55, east on I-10, then south on I-310 to between US 61 and LA 48 (or vice versa) and be on bridge the entire time...a total of a little over 38 miles.

[Mapmikey]

I'd also say if it is a bridge only over water, the Virginia Dare memorial bridge is 5.2 mi long and connects the outer banks to the mainland.

https://en.wikipedia.org/wiki/Virginia_Dare_Bridge

Slightly longer is the I-10 twin span: https://en.wikipedia.org/wiki/I-10_Twin_Span_Bridge

There's always the 7-mile bridge in the Florida Keys...

For Virginia, both the US 17-258 James River and I-664 James River bridges are longer than the Hampton Roads Bridge-Tunnel. 

US 17-258 is longest at about 4.4 miles.

Mapmikey

[doorknob60]

Not as long as some of the others, but the Astoria—Megler Bridge is 4.1 miles long.

[roadman65]

How could I forget about the 7 mile bridge?  I have been across it many times in my younger days.

[Alps]

There's always the 7-mile bridge in the Florida Keys...

My first thought, indeed.

Technically speaking (and something we've had a thread about here in the past), one could start at the north end of the Manchac Swamp Bridge and go south on I-55, east on I-10, then south on I-310 to between US 61 and LA 48 (or vice versa) and be on bridge the entire time...a total of a little over 38 miles.

Since I'm an engineer, I have to be picayune - is it a "bridge" just because it's up on structure, or does it have to have a name to it as a defined set of spans? Could go either way, not sure what the thread is looking for.

[hm insulators]

In Los Angeles, I-10 between I-110 and the East L.A. Interchange is on bridge rather than above-grade fill.

Just west of Sacramento, the Yolo Causeway bridges on I-80 are pretty long.

[agentsteel53]

In Los Angeles, I-10 between I-110 and the East L.A. Interchange is on bridge rather than above-grade fill.

similarly, the Alaskan Way viaduct in Seattle.