Norfork Bridge (Baxter County, Arkansas)
Construction started Aug. 21, 1936, by the Vincennes Steel Company; dedicated June 17, 1937
Four-span deck truss bridge over North Fork White River on AR 5 at Norfork
Open to traffic

Norfork Railroad Bridge (Baxter County, Arkansas)
Built ca. 1909
Three-span through truss bridge over North Fork White River and Prospect Street on the railroad at Norfork
Open to railroad traffic

Norris Ford Bridge (Rush County, Indiana)
Built 1916 by E. L. Kennedy
Covered bridge over Flatrock River on CR 300 North
Open to traffic

North Avenue Bridge (Cook County, Illinois)
Built 1907
Double-leaf bascule through truss bridge over North Branch Chicago River on North Avenue in Chicago
Open to two-lane traffic

North Big River Bridge (St. Francois County, Missouri)
Built 1924; made obsolete by new bridge in 1956
Through truss bridge over Big River on Old US 67 (Berry Road) north of Bonne Terre
Open to one-lane traffic

North Boat Ditch Bridge (Clark County, Arkansas)
Built ca. 1928
Through truss bridge over North Boat Ditch on CR 8
Open to one-lane traffic

North Boat Ditch US 67 Bridge (Clark County, Arkansas)
Built 1931 by the Virginia Bridge & Iron Co. of Roanoke, Virginia
Pony truss bridge over North Boat Ditch of Terre Noire Creek on US 67
Open to traffic

North Branch Root River Bridge (Fillmore County, Minnesota)
Built 1939
Through truss bridge over North Branch Root River on CR 124
Open to traffic

North Branch Root River MN 250 Bridge (Fillmore County, Minnesota)
Built 1924
Through truss bridge over North Branch Root River on MN 250
Open to traffic

North Broadway Bridge (Los Angeles County, California)
Built 1909; rehabilitated 1974
Concrete arch bridge over L A Riv,Bnsf,Uprr,Metro, on North Broadway in Los Angeles
Open to traffic

North Cayuga Street Bridge (Tompkins County, New York)
Built 1934; rehabilitated 2002
Pony truss bridge over Fall Creek on North Cayuga Street in Ithaca
Open to traffic

North Cut Ditch Bridge (Scott County, Missouri)
Built 1923; rehabilitated 1941
Through truss bridge on MO 77 over North Cut Ditch northwest of Diehlstadt
Open to one-lane traffic

North Fork Big Nemaha River Bridge (Richardson County, Nebraska)
Built 1955
Truss bridge over North Fork Big Nemaha River on NE 8 in Salem
Open to traffic

North Fork Little Maquoketa River Bridge (Dubuque County, Iowa)
Built 1901
Pony truss bridge over North Fork Little Maquoketa River on a local road
Open to traffic

North Fork MO 126 Bridge (Barton County, Missouri)
Built 1954
Three-span pony truss bridge over North Fork Spring River on MO 126
Open to two-lane traffic

North Fork Route H Bridge (Jasper County, Missouri)
Built 1933
Pony truss bridge over North Fork Spring River on Route H
Open to traffic

North Fork Route M Bridge (Jasper County, Missouri)
Built 1949
Pony truss bridge over North Fork Spring River on Route M (Baseline Road) in Carytown
Open to two-lane traffic

North Lake Railroad Bridge (Waukesha County, Wisconsin)
Built 1911
Bridge over Wisc 83 on UPRR (Formerly C&NW) in North Lake (Town of Merton)
Open to traffic

North River Bridge (Madison County, Iowa)
Built ca. 1920; rehabilitated 1967
Through truss bridge over North River on a local road
Open to traffic

North River MO 168 Bridge (Marion County, Missouri)
Built 1932
Four-span through truss bridge over North River on MO 168, west of Palmyra
Open to two-lane traffic

North Spring Street Bridge (Los Angeles County, California)
Built 1928; rehabilitated 1939, seismic upgrade 1992
Concrete arch bridge over Los Angeles River on North Spring Street in Los Angeles
Open to traffic

North Wea Creek Bridge (Miami County, Kansas)
Built ca. 1920
Pony truss bridge over North Wea Creek, 2.2 mi. north and 2.0 mi. west of Louisburg
Open to traffic

North Wea Creek Bridge (Miami County, Kansas)
Built ca. 1910
Pony truss bridge over North Wea Creek, 4.3 mi. west and 2.0 mi. north of Louisburg
Open to traffic

Norway Road Bridge (Newton County, Missouri)
Relocated here 1995
Pony truss bridge over Elm Spring Branch on Norway Road, just off Route HH
Open to two-lane traffic

Nut Junction Bridge (Cape Girardeau County, Missouri)
Built 1938
Pony plate girder bridge over the Castor River Diversion Channel on Route N just east of the intersection with Route U and Route T
Open to two-lane traffic with no posted weight limit

O'Neal Bridge (Independence County, Arkansas)
Built ca. 1933, possibly by the Works Progress Administration
Small five-span closed-spandrel arch bridge over O'Neal Creek on O'Neal Road (CR 37)
Open to traffic

Oak Dale Road Bridge (Moniteau County, Missouri)
Built ca. 1930
Through truss bridge over Straight Fork on Oak Dale Road northwest of Latham
Open to one-lane traffic with a 15 ton weight limit

Oak Grove Bridge (Madison County, Missouri)
Built 1922; made obsolete by new bridge in 1972
Pony truss bridge over Barnes Creek on CR 504 (Old MO 72, formerly MO 70) west of Fredericktown
Open to traffic on a paved road

Oak Leaf Bike Trail Bridge (Milwaukee County, Wisconsin)
Stone arch bridge over Hubbard Park Drive on Oak Leaf Bike Trail in Shorewood
Open to traffic

Oakalla Covered Bridge (Putnam County, Indiana)
Built 1898 by J.J. Daniels
Covered bridge over Big Walnut Creek on CR 375W
Open to traffic

Occoquan River Bridge (Prince William County, Virginia)
Parker through truss bridge over Occoquan River on Richmond, Fredericksburg and Potomac Railroad
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 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 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 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 Bridge (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 Hollow Bridge (Fountain County, Indiana)
Built ca. 1920
Concrete arch bridge over Opossum Hollow on CR 1300 North
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 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

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

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 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

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