Occoquan River Bridge (Prince William County, Virginia)
Parker through truss bridge over Occoquan River on Richmond, Fredericksburg and Potomac Railroad
Open to traffic

Ocean Avenue Bridge over Santa Monica Freeway (Los Angeles County, California)
Built 1935
Concrete arch bridge over I-10 on Ocean Avenue in Santa Monica
Open to traffic

Oconomowoc River Bridge (Waukesha County, Wisconsin)
Built 1910
Concrete arch bridge over Oconomowoc River on West Second Street in Oconomowoc
Open to traffic

Oconomowoc River Bridge (Waukesha County, Wisconsin)
Built 1916
Concrete arch bridge over Oconomowoc River on WI 83
Open to traffic

Oconomowoc River CPRR Arch Bridge (Waukesha County, Wisconsin)
Built 1902 by The Milwaukee Road Railroad (CMStP&P RR)
Closed-spandrel arch bridge over Oconomowoc River on Canadian Pacific Railroad in Oconomowoc
Open to traffic

Oconomowoc River Hwy 16 Bridge (Waukesha County, Wisconsin)
Built 1924
Stringer bridge over Oconomowoc River on Wisc 16 - West Wisconsin Avenue in Oconomowoc
Open to traffic

Offutt's Ford Covered Bridge (Rush County, Indiana)
Built 1884 by Kennedy Bros.
Covered bridge over Little Blue River on Offutt Bridge Road
Open to traffic

Ohio River I-77 Bridge (Washington County, Ohio)
Through truss bridge over the Ohio River on I-77 near Marietta
Open to traffic

Okamanpedan State Park Bridge (Emmet County, Iowa)
Built 1914; rehabilitated 1923
Pony truss bridge over East Fork Des Moines River on Tuttle Lake Road at Okamanpedan State Park
Open to one-lane traffic

Okatibbee Creek Bridge (Lauderdale County, Mississippi)
Built 1926
Pony truss bridge over Okatibbee Creek on Old US 80 in Meridian
Open to traffic

Old Appleton US 61 Bridge (Cape Girardeau County, Missouri)
Built 1931
Pony truss bridge over Apple Creek on US 61 at Old Appleton
Open to two-lane traffic on a dangerous curve

Old Barn Bridge (Fillmore County, Minnesota)
Built 1914
Through truss bridge over Mill Pond South Branch Root on Heron Rd.
Open to traffic

Old Canal Bridge (Madison County, Illinois)
Built 1949; rehabilitated 1999
Through truss bridge over Chain of Rocks Canal on Old Chain of Rocks Road (at one time US 66) just south of I-270 in Granite City
Open to one-lane highway traffic with a dedicated bike lane

Old Cannons Lane Bridge (Jefferson County, Kentucky)
Built ca. 1960
Concrete arch bridge over Middle Fork Beargrass Creek on Old Cannons Lane in Louisville
Open to traffic

Old Clay's Ferry Bridge (Fayette County, Kentucky)
Built 1871; rehabilitated 1955
Two-span through truss bridge over Kentucky River on KY 2328 (Old US 25) in Lexington
Open to traffic

Old Erie Canal Bridge (Carroll County, Indiana)
Built 1901
Stone arch bridge over Old Erie Canal on Bicycle Bridge Road in Delphi
Open to traffic

Old Five Road Bridge (Morgan County, Missouri)
Built 1922
Pony truss on Old Five Road over a branch of Little Gravois Creek
Open to traffic

Old Gurdon Highway Bridge (Clark County, Arkansas)
Concrete tee-beam bridge on Old Gurdon Highway two miles south of Beirne. Unknown builder and date.
Concrete tee beam bridge over Boggy Creek on Old Gurdon Highway
Open to traffic

Old Highway 66 Bridge (Warrick County, Indiana)
Built 1941
Two span Parker through truss bridge over Little Pigeon Creek on Old Highway 66
Open to traffic

Old Hundred (Wetzel County, West Virginia)
Built 1933
Bridge over Church Fork Creek on Us 250
Open to traffic

Old Katy Bridge (Geary County, Kansas)
Built 1913 by the Pencoyd Bridge & Construction Co.
Through truss bridge over Lyon Creek on Otter Creek Road, just southeast of Wreford
Open to traffic

Old Mo. 21 (Washington County, Missouri)
Built 1925
Bridge over Breton Creek on Old Alignment of Mo. 21 in Potosi
Open to traffic

Old Mo. 32 (St. Francois County, Missouri)
Built 1924
Bridge over Unnamed creek on Old Alignment of Mo. 32
Open to traffic

Old Monroe Railroad Bridge (Lincoln County, Missouri)
Three-span through truss bridge over Cuivre River on the BNSF Railroad at Old Monroe
Open to railroad traffic

Old Richardsville Road Bridge (Warren County, Kentucky)
Built 1889
Three span Bowstring Arch Truss bridge over Barren River on Old Richardsville Road in Bowling Green
Open to traffic

Old River Road Bridge (Warrick County, Indiana)
Built 1893
Through truss bridge over Little Pigeon Creek on Old River Road
Open to traffic

Old Route E Bridge (Newton County, Missouri)
Built 1922; made obsolete by bridge on new alignment in 1974
Five-span arch bridge over Shoal Creek on Old Route E, northwest of Granby
Open to traffic

Old Rudy Way Bridge (Crawford County, Arkansas)
Built 1940 by the Works Progress Administration
Stringer bridge with stone piers over an unnamed creek on Old Rudy Way (CR 19) just off AR 282 at Rudy
Open to traffic

Old Rusty Bridge (Clay County, Iowa)
Built 1901 by the Clinton Bridge & Iron Works; relocated here in 1915
Through truss bridge over Little Sioux River on 210th Avenue north of Spencer in Spencer
Open to one-lane traffic

Old Scotland Bridge (Boone County, Indiana)
Built 1901
Three-span stone arch bridge over Sugar Creek on CR 200E
Open to traffic

Old Stable Bridge (St. Louis, Missouri)
Built 1922; rehabilitated 2003
Replica concrete arch bridge on Theatre Drive in Forest Park
Open to traffic

Old Stone Bridge (Davidson County, Tennessee)
Built ca. 1837-1849 as part of the Louisville & Nashville Turnpike
Stone arch bridge on Old Stone Bridge Rd. (Former Louisville and Nashville Turnpike) in Goodlettsville
Open to traffic

Old Topanga Road Bridge (Los Angeles County, California)
Built 1927; rehabilitated 1960
Wooden bridge over Old Topanga Creek on Old Topanga Road in Los Angeles
Open to traffic

Old US 50 Viaduct (Cooper County, Missouri)
Built 1924
Tee beam bridge over the Union Pacific Railroad on Old US 50, just north of current US 50
Open to traffic

Old Wire Road Tunnel (Benton County, Arkansas)
Short tunnel under the Arkansas-Missouri Railroad on Old Wire Road near Avoca
Open to railroad traffic above and road traffic below

Olena Road Bridge (Arkansas County, Arkansas)
Built 1936
Small arch bridge over a drainage ditch on Olena Road (CR 402)
Open to one-lane traffic

Olin Covered Bridge (Ashtabula County, Ohio)
Built 1873; reconstructed 1993
Covered bridge over Ashtabula River on Dewey Road (TH 334) in Edgewood
Open to traffic

Olympic Boulevard over the Los Angeles River (Los Angeles County, California)
Built 1925
Concrete arch bridge over Los Angeles River and railroad tracks on Olympic Boulevard in Los Angeles
Open to traffic

Oneota Drive Bridge (Winneshiek County, Iowa)
Built 1948
Pony truss bridge over Drainage Channel on Oneota Drive in Decorah
Open to traffic

Opossum Creek IN 263 Bridge (Warren County, Indiana)
Built 1936
Concrete arch bridge over Opossum Creek on IN 263
Open to traffic

Opossum Hollow Bridge (Fountain County, Indiana)
Built ca. 1920
Concrete arch bridge over Opossum Hollow on CR 1300 North
Open to traffic

Orange & Hill Viaduct (Los Angeles County, California)
Built 1932
Steel stringer bridge over Orange Ave Oh (Sptco) on Orange Ave & Hill S in Long Beach
Open to traffic

Orange Road Bridge (Delaware County, Ohio)
Built 1898 by the Toledo Bridge Co.; rehabilitated 1970
Through truss bridge over Olentangy River on Orange Road (TR 114) in Powell
Open to one-lane traffic

Oregon City Covered Bridge (Butte County, California)
Built 1983 by Clay Castleberry
Modern covered bridge over Oregon Gulch Creek on Oregon Gulch Road at Oregon City
Open to traffic

Oregon Creek Covered Bridge (Yuba County, California)
Built 1860 by Thomas Freeman
Covered bridge over Oregon Creek on Alleghany Road at Oregon Creek Campground
Open to traffic

Oriental Covered Bridge (Juniata County, Pennsylvania)
Built 1908; rehabilitated 1987
Covered bridge over West Branch Mahantango Creek on PA 2023
Open to traffic

Oriole Bridge (Cape Girardeau County, Missouri)
Built 1953
Stringer bridge with steel and wood piers over Little Indian Creek on Route V at Oriole
Open to two-lane traffic

Oronoco Bridge (Olmsted County, Minnesota)
Built 1918; rehabilitated 1987. Originally replaced an iron truss bridge built by Horrace E. Horton
Open-spandrel arch bridge over Zumbro River on CSAH 18 at Oronoco
Open to traffic

Orr Road Bridge (Washington County, Arkansas)
Built 1924
Through truss bridge over Illinois River on Orr Road (CR 67) just off AR 265, southeast of Prairie Grove
Open to one-lane traffic

Orten Creek Bridge (Scott County, Arkansas)
Built 1915; rehabilitated 1984
Pony truss bridge over Orten Creek on CR 60
Open to one-lane traffic

Osage City Railroad Bridge (Cole County, Missouri)
Through truss bridge on the Union Pacific Railroad over Osage River at Osage City
Still in use

Osage Creek Bridge (Benton County, Arkansas)
Built 1911 by the Youngstown Bridge Co. of Youngstown, Ohio
Through truss bridge over Osage Creek on CR 71 southeast of Healing Springs
Open to one-lane traffic

Osage Fork MO 32 Bridge (Laclede County, Missouri)
Built 1933
Through truss bridge over Osage Fork on MO 32
Open to traffic

Osage Fork MO 5 Bridge (Laclede County, Missouri)
Built 1932
Three-span pony truss bridge over Osage Fork on MO 5 in Twin Bridges
Open to traffic

Osage Valley Road Bridge (Cooper County, Missouri)
Built 1913; rehabilitated 1993
Pony truss bridge over Petite Saline Creek on Osage Valley Road
Open to traffic

Ottawa Street Bridge (Newton County, Missouri)
Built by the Canton Bridge Co.
Pony truss bridge over Little Lost Creek on Ottawa Street in Seneca
Open to traffic

Otter Creek Bridge (Chautauqua County, Kansas)
Built 1936 by the Works Progress Administration
Through truss bridge over Otter Creek, 4.2 mi. north of Cedarvale
Open to traffic

Otterville Railroad Bridge (Cooper County, Missouri)
Built 1938
Two-span pony plate girder railroad bridge over Lamine River, parallel with Route A
Open to railroad traffic

Ouachita River CR 76 Bridge (Polk County, Arkansas)
Built 1914
Pony truss bridge over Ouachita River on CR 76
Open to one-lane traffic

Ouachita River US 67 Bridge (Hot Spring County, Arkansas)
Built 1929; rehabilitated 1957
Three-span arch bridge over Ouachita River on US 67
Open to traffic

Owens Creek Main City Road Bridge (Cass County, Missouri)
Built ca. 1940
Pony truss bridge over Owens Creek on Main City Road
Open to traffic

Owens Ditch Bridge (Benton County, Indiana)
Built ca. 1920
Pony truss bridge over Owens Ditch on CR 225 North
Open to traffic

Owens Mill Bridge (Cedar County, Missouri)
Built ca. 1910 by the Canton Bridge Co.
Through truss bridge over Bear Creek on CR 1801
Open to one-lane traffic

Owl Creek Bridge (Allen County, Kansas)
Built 1909
Pony truss bridge over Owl Creek, 3.4 mi. west of Humboldt
Open to traffic

Oxly Military Road Bridge (Ripley County, Missouri)
Built ca. 1930
Wooden deck bridge over Logan Creek on CR 142E-30 (Old Military Road), just south of Oxly
Open to one-lane traffic

Ozark Bridge (Franklin County, Arkansas)
Built 1930 as a six-span concrete arch bridge; bridge rehabilitated and main span replaced in 1970
Steel through arch bridge over the Arkansas River on AR 23 at Ozark
Open to two-lane traffic

Ozark Mill Bridge (Christian County, Missouri)
Two-span through truss bridge over Finley Creek on W. McCracken Street (Old US 65) in Ozark
Open to traffic

Pa Fork of Fish Creek Bridge (Marshall County, West Virginia)
Built 1924
Through truss bridge over Pa Fork of Fish Creek on US 250
Open to traffic

Pacific Coast Highway over Las Flores Creek (Los Angeles County, California)
Built 1926; rehabilitated 1931
Concrete tee beam bridge over Las Flores Creek on Pacific Coast Highway (CA 1) in Malibu
Open to traffic

Paducah Bridge (McCracken County, Kentucky)
Built 1973
Two-span tied-arch bridge on Interstate 24 over the Ohio River between Paducah, KY, and Metropolis, IL
Open to four lanes of traffic

Page Avenue Bridge (St. Louis County, Missouri)
Opened Dec. 13, 2003
Pair of tied arch bridges over the Missouri River on MO 364 (Page Avenue)
Open to traffic

Paint Creek Bridge (Fayette County, Ohio)
Built 1928; rehabilitated 1960
Truss bridge over Paint Creek on Old US 35
Open to traffic

Paint Creek CR 150E Bridge (Carroll County, Indiana)
Built 1903
Pony truss bridge over Paint Creek on CR 150 East
Open to traffic

Palisades Bridge (Minnehaha County, South Dakota)
Built 1881 by S.M. Hewitt & Co.
Through truss bridge over Split Rock Creek on 485th Avenue at Palisades State Park
Open to one-lane traffic

Palm Tree Road Bridge (Fond du Lac County, Wisconsin)
Stone arch bridge over Sheboygan River on Palm Tree Road
Open to traffic

Paoli Pike Bridge (Floyd County, Indiana)
Built 1921
Two-span concrete arch bridge over Little Indian Creek on Paoli Pike
Open to traffic

Paradise Creek Bridge (Russell County, Kansas)
Built 1935
Stone arch bridge over Paradise Creek, 1.0 mi. south and 0.5 mi. east of Paradise
Open to traffic

Paradise Creek Bridge (Russell County, Kansas)
Built 1901
Stone arch bridge over Paradise Creek
Open to traffic

Paradise Creek Bridge (Russell County, Kansas)
Built 1917
Stone arch bridge over Paradise Creek, 1.0 mi. east and 2.0 mi. south of Paradise
Open to traffic

Paris Railroad Bridge (Monroe County, Missouri)
Through truss bridge over Middle Fork Salt River on the Norfolk Southern Railroad in Paris
Open to railroad traffic

Park Row over the Pasadena Freeway (CA 110) (Los Angeles County, California)
Built 1942
Arch bridge over Pasadena Freeway (CA 110) on Park Row in Los Angeles
Open to traffic

Parkdale Bridge (Fremont County, Colorado)
Built ca. 1915
Pony truss bridge over Arkansas River near Parkdale on CR 157 just off US 50
Open to traffic

Parker Bridge (Armstrong County, Pennsylvania)
Built 1934
Four-span through truss bridge over Allegheny River on PA 368 at Parker
Open to traffic

Parr's Mill Covered Bridge (Columbia County, Pennsylvania)
Built 1865
Covered bridge over Roaring Creek on Parrs Mill Road, south of Catawissa
Open to traffic

Paseo Bridge (Jackson County, Missouri)
Built 1954; rehabilitated 1984
Suspension bridge across the Missouri River on I-29/I-35/US 71 in Kansas City
Open to traffic

Patoka River Bridge (Orange County, Indiana)
Built 1884
Through truss bridge over Patoka River on CR 850 South
Open to traffic

Patoka River Bridge (Orange County, Indiana)
Built 1888
Through truss bridge over Patoka River on CR 180 East
Open to traffic

Patoka River Bridge (Orange County, Indiana)
Built 1885; rehabilitated 1992
Through truss bridge over Patoka River on CR 700 South
Open to traffic

Patterson Bridge (Wayne County, Missouri)
Built ca. 1922
Two-span pony truss bridge over Clark Creek near Patterson on CR 312 (Old MO 34)
Open to traffic with a 21 ton limit on a paved road

Patton Bridge (Bollinger County, Missouri)
Built 1922
Two-span pony truss bridge over Little Whitewater River on MO 51 in Patton
Open to two-lane traffic on a paved road

Paup's Spur Bayou Old US 67 Bridge (Miller County, Arkansas)
Built 1929 by contractor McGuire & Cavender. Made obsolete 1954 by a new parallel alignment of US 67.
Concrete bridge over Paup's Spur Bayou on CR 138 (Old US 67) northeast of Texarkana
Open to traffic on a frontage road

Pawnee Creek Bridge (Bourbon County, Kansas)
Built 1929
Through arch bridge over Pawnee Creek, 4.0 mi. north and 2.4 mi. east of Hiattville
Open to traffic

Peace Valley Road Bridge (Sharp County, Arkansas)
Built 1936
Small two-span arch bridge over an unnamed creek on Peace Valley Road (CR 46)
Open to traffic

Pecos River Flume (Eddy County, New Mexico)
Built ca. 1903
Four-span concrete arch aqueduct carrying Southern Main Canal over Pecos River at Carlsbad
Still carries water

Pecos River High Bridge (Val Verde County, Texas)
Built 1944, replacing an earlier 1892 viaduct
Massive cantilevered deck truss bridge over Pecos River on the Union Pacific Railroad
Open to traffic

Pee Wee Reese Road (Jefferson County, Kentucky)
Built ca. 1930
Concrete arch bridge over Middle Fork Beargrass Creek on Pee Wee Reese Road in Louisville
Open to traffic

Penns Creek US 522 Bridge (Snyder County, Pennsylvania)
Built 1941
Two-span through truss bridge over Penns Creek on PA 522 in Selinsgrove
Open to traffic

Perrine Bridge (Twin Falls County, Idaho)
Built 1976
Steel arch bridge over Snake River on US 93 at Twin Falls
Open to traffic

Perry Bridge (Jefferson County, Kansas)
Built 1926 by the Midland Bridge Co.
Through truss bridge over Delaware River on Bridge Street (Old US 24) just west of Perry in Perry
Open to two-lane traffic

Perry County Road 838 Bridge (Perry County, Missouri)
Built 1905; reconstructed 1986
Bedstead pony truss bridge over a branch of Saline Creek on CR 838
Open to traffic