Pontoon

Bridges that float on top of the water much like a boat but not held to the bottom of bodies of water.

Arkansas River Pontoon Bridge (Yell County, Arkansas)
At one time owned by the Dardanelle and Russellville Railroad, but no trains ever crossed it.
Lost Pontoon bridge over Arkansas River in Dardanelle. Once hailed as the "Longest pontoon bridge over moving water". Carried Old Military Road, a major route between Little Rock and Fort Smith.
Demolished

Brookfield Floating Bridge (Orange County, Vermont)
Built 1936; rehabilitated 1978
Pontoon bridge over Sunset Lake on Route 65 in Brookfield
Closed to all traffic

Butte Larose Pontoon Bridge (St. Martin Parish, Louisiana)
Built 1960
Pontoon lift bridge over Crocodile Bayou on Herman Dupuis Rd
Open to traffic

Cote Blanche Bridge (Lafourche Parish, Louisiana)
Built 1956
Bridge over Bayou Lafourche on Local road
Open to traffic

Dulac Pontoon Bridge (Terrebonne Parish, Louisiana)
Built 1958
Swing bridge over Houma Navigation Canal on Falgout Canal Rd in Dulac
Open to traffic

Elk Springs Pontoon Bridge (McDonald County, Missouri)
Replaced 1935(?)
Lost pontoon bridge over Elk River on Elk Springs Road
Replaced by new bridge

Estherwood Bridge (Acadia Parish, Louisiana)
Built 1975
Pontoon bridge over Bayou Plaquemine Brule on LA 91 at Estherwood
Open to traffic

Evergreen Point Floating Bridge (King County, Washington)
Built 1963
Pontoon bridge over Lake Washington on SR 520
Open to traffic

Galliano Pontoon Bridge (Lafourche Parish, Louisiana)
Built 1956; rehabilitated 2009
Bascule bridge over Bayou Lafourche at Galliano
Open to traffic

Homer M. Hadley Memorial Bridge (King County, Washington)
Built 1989
Pontoon bridge over Lake Washington on W.B. & Rev I-90
Open to traffic

Hood Canal Bridge (Kitsap County, Washington)
Built 1961, Sank 1979, Reopened 1982, East half replaced 2009
Pontoon bridge over Hood Canal on WA 104
Open to traffic

Intracoastal Waterway Bridge (Brunswick County, North Carolina)
Built 1961
Swing bridge over Intracoastal Waterway on NC 1172 in Sunset Beach
Open to traffic

Little Sioux River Pontoon Bridge (Cherokee County, Iowa)
Lost Pontoon bridge on Road
Replaced by a new bridge

MILW Pile-Pontoon Bridge (Clayton County, Iowa)
Built 1874, Rebuilt several times, Diassembled 1961
Lost Pontoon bridge over Mississippi River on railroad
Lost