US Bridges

Iowa bridges

Iowa reports 23,716 bridges and culverts across 99 counties. 4,423 (18.6%) are rated in poor condition, and 4,708 are posted with load limits or closed. The oldest structure still in the inventory dates from 1876.

Bridges
23,716
Counties
99
Good
39%
Fair
42%
Poor
19%
4,423 bridges
Average age
45.5 yrs

Find a bridge in Iowa

Type at least two characters, or pick a condition or type, to search every bridge in the state.

Counties

Circle size reflects the number of bridges

Condition

19%poor
Good39%(9,329)
Fair42%(9,964)
Poor19%(4,423)

Counties with the highest share of poor bridges

Poor-condition bridgesFairGood

Structure types

Structure typeBridgesShare
Stringer/Multi-beam or Girder10,70045.1%
Slab5,67923.9%
Culvert4,93620.8%
Tee Beam1,0144.3%
Truss - Thru6422.7%
Channel Beam3691.6%
Girder and Floorbeam System1400.6%
Arch - Deck840.4%
Other570.2%
Box Beam or Girders - Multiple520.2%
Arch - Thru170.1%
Frame170.1%
Truss - Deck40.0%
Box Beam or Girders - Single or Spread20.0%
Suspension10.0%
Stayed Girder10.0%
Segmental Box Girder10.0%

When Iowa's bridges were built

<1900: 24 bridges24<19001900s: 546 bridges54619001910s: 335 bridges33519101920s: 524 bridges52419201930s: 611 bridges61119301940s: 752 bridges75219401950s: 2,323 bridges2.3k19501960s: 2,742 bridges2.7k19601970s: 3,575 bridges3.6k19701980s: 2,907 bridges2.9k19801990s: 2,776 bridges2.8k19902000s: 3,011 bridges3.0k20002010s: 2,504 bridges2.5k20102020s: 1,086 bridges1.1k2020
Bridges built per decade. Year built as recorded in the inventory; reconstruction years are not included.

Busiest

  1. I-235 over Drainage Ditch
    Polk County · 118,600 vehicles/day
    Fair
  2. I-235 & 17th ST over Blue Creek
    Polk County · 113,200 vehicles/day
    Fair
  3. I29 NB Off Ramp over Perry Creek Conduit
    Woodbury County · 91,000 vehicles/day
    Good
  4. I 235 over Des Moines Rvr Rbrtraydr
    Polk County · 88,200 vehicles/day
    Good
  5. I-35 & I-80 over N Walnut Creek
    Polk County · 81,600 vehicles/day
    Fair

Longest

  1. US 20 over Miss. River HWY & RR
    Dubuque County · 5,760 ft
    Fair
  2. Ia 14 over Des Moines River & Res
    Marion County · 5,653 ft
    Fair
  3. Ia 415 over Saylorville Reservoir
    Polk County · 4,933 ft
    Fair
  4. US 275 & Ia 92 over Missouri River and RR
    Pottawattamie County · 4,297 ft
    Good
  5. I-280 over Mississippi River & Road
    Scott County · 4,193 ft
    Fair

Oldest

  1. Local-Dead End over Skunk River
    Story County · Built 1876
    Poor
  2. Local over Br Des Moines River
    Marion County · Built 1878
    Poor
  3. Sutton RD over Wapsipinicon River
    Linn County · Built 1879
    Poor
  4. Local 25th ST over Upper Iowa River
    Howard County · Built 1880
    Poor
  5. Local over North Raccoon River
    Dallas County · Built 1882
    Poor

Newest

  1. I 80 EB Ia 38 SB over Sugar Creek
    Cedar County · Built 2024
    Good
  2. I 80 WB Ia 38 NB over Sugar Creek
    Cedar County · Built 2024
    Good
  3. Ia 150 over Prairie Creek
    Benton County · Built 2024
    Good
  4. US 59 over E Br W Nishnabotna Rvr
    Pottawattamie County · Built 2024
    Good
  5. Ia 9 over Beaver Creek
    Worth County · Built 2024
    Good

Who owns Iowa's bridges

County18,19276.7%
State4,21417.8%
City1,2755.4%
Federal290.1%
Local40.0%
Private10.0%
Railroad10.0%

More Iowa facts

Total bridge length505 miles
Total deck area98,886,152 sq ft
Culverts counted as bridges4,936 (21%)
On the National Highway System2,659
Posted with load limits4,378
Closed to traffic330
Listed or eligible for the National Register102
Average daily traffic per bridge1,473 vehicles
Newest structure2024