Carver Creek Bridge (Iron County, Missouri)
Built 1932
Pony truss bridge over Carver Creek on MO 21/49/72 east of Lesterville
Open to two-lane traffic

Ellington Bridge (Reynolds County, Missouri)
Built 1921; replaced when the new alignment of MO 21 was built in 1967
Lost five-span pony truss bridge over Logan Creek on MO 21 at Ellington
Replaced by a new bridge

Gum Spring Old MO 21 Bridge (Iron County, Missouri)
Built 1922; made obsolete by a new alignment of MO 21
Arch bridge over Gum Spring Creek on CR 20 (Old MO 21)
Open to traffic

Ironton Bridge (Iron County, Missouri)
Built 1926
Tee beam bridge over Stouts Creek on Old MO 21 between Ironton and Arcadia
Open to traffic

Meramec River MO 21 Bridge (St. Louis County, Missouri)
Built 1940
Steel through arch bridge over the Meramec River on MO 21
Open to four lanes of traffic

Mill Creek Bridge (Reynolds County, Missouri)
Built 1921; abandoned ca. 2002; razed 2004-05
Lost concrete slab bridge on CR 360 (Old MO 21) over Mill Creek east of Lesterville
No longer exists

Old Mines Bridge (Washington County, Missouri)
Built 1923; rehabilitated 1933; replaced Summer 2007
Lost pony truss bridge over Old Mines Creek on MO 21
Replaced by a new bridge

Pyrtle Spring Bridge (Reynolds County, Missouri)
Built 1923; made obsolete by a new bridge in 1968
Three-span pony truss bridge over Sinking Creek on Old MO 21
Open to traffic on a paved road with a 12 ton weight limit

Second Mill Creek Bridge (Reynolds County, Missouri)
Built 1921
Concrete slab bridge with ballusters on CR 360 (Old MO 21) east of Lesterville
Open to traffic with a 5 ton weight limit

Townsend Branch Old MO 21 Bridge (Iron County, Missouri)
Built 1922; made obsolete by a new alignment of MO 21
Arch bridge over Townsend Branch on CR 20 (Old MO 21)
Open to traffic