Longest Bridges in Montana
The longest bridge in Montana is the Koocanusa Bridge over Koocanusa Reservoir, at 0.5 miles (2,437 ft) of total structure length. The table below ranks the longest bridges in Montana by structure length.
| Bridge | County | Length | Year Built | Daily Traffic |
|---|---|---|---|---|
| Koocanusa Bridge over Koocanusa Reservoir | Lincoln | 2,437 ft (0.5 mi) | 1971 | 75 |
| US 87-mt 3-mt 200 over Missouri River-u5205-rr | Cascade | 2,121 ft (0.4 mi) | 1983 | 13,666 |
| US 89-mt 3-mt 200 over Missouri River-u5205-rr | Cascade | 2,092 ft (0.4 mi) | 1951 | 13,666 |
| I 94 over Yellowstone River | Dawson | 2,013 ft (0.4 mi) | 1968 | 2,109 |
| I 94 over Yellowstone River | Dawson | 1,973 ft (0.4 mi) | 1968 | 2,981 |
| Bbp over Yellowstone River | Yellowstone | 1,858 ft (0.4 mi) | 2022 | 100 |
| Montana AVE over U1024-25-rr | Yellowstone | 1,712 ft (0.3 mi) | 1960 | 8,576 |
| Montana AVE over U1025-rr | Yellowstone | 1,710 ft (0.3 mi) | 1960 | 8,576 |
| IRR - US 93 over Flathead River | Lake | 1,536 ft (0.3 mi) | 1966 | 8,557 |
| IRR - US 2 over Two Medicine River | Glacier | 1,520 ft (0.3 mi) | 2012 | 1,939 |
| S 200s-towne ST over Yellowstone River | Dawson | 1,322 ft (0.3 mi) | 1958 | 8,821 |
| I 15 over Missouri Rvr-rr-local | Lewis and Clark | 1,287 ft (0.2 mi) | 1971 | 2,201 |
| I 90 EB over Clark Fork Rvr-local RD | Mineral | 1,282 ft (0.2 mi) | 1982 | 3,559 |
| I 15 over Missouri Rvr-rr-local | Lewis and Clark | 1,249 ft (0.2 mi) | 1971 | 2,201 |
| S 37 Fh 57 over Kootenai River | Lincoln | 1,236 ft (0.2 mi) | 1969 | 661 |
| 9th ST N over Missouri River | Cascade | 1,232 ft (0.2 mi) | 1996 | 14,024 |
| I 94 over Yellowstone River | Prairie | 1,169 ft (0.2 mi) | 1978 | 2,219 |
| I 94 over Yellowstone River | Prairie | 1,169 ft (0.2 mi) | 1978 | 2,219 |
| I 90 WB over Clark Fork Rvr-local RD | Mineral | 1,144 ft (0.2 mi) | 1984 | 3,559 |
| Frontage Road 114 over Yellowstone River 015 | Prairie | 1,144 ft (0.2 mi) | 1945 | 100 |
| 15th ST N-us 87 over Missouri R-rivers Trail | Cascade | 1,125 ft (0.2 mi) | 1962 | 14,369 |
| S 200 over Clark Fork River | Sanders | 1,109 ft (0.2 mi) | 1997 | 3,009 |
| S 23 over Yellowstone River | Richland | 1,102 ft (0.2 mi) | 1994 | 2,438 |
| I 90 over Clark Fork River | Mineral | 1,091 ft (0.2 mi) | 1982 | 3,719 |
| I 90 over Clark Fork River | Mineral | 1,091 ft (0.2 mi) | 1984 | 3,719 |
| York RD over Missouri River | Lewis and Clark | 1,079 ft (0.2 mi) | 1982 | 551 |
| Milwaukee RD over Yellowstone River 030 | Prairie | 1,077 ft (0.2 mi) | 1907 | 37 |
| Tusler RD over Yellowstone River 094 | Custer | 1,063 ft (0.2 mi) | 1907 | 78 |
| S 200 over Clark Fork River | Sanders | 1,061 ft (0.2 mi) | 1958 | 2,069 |
| IRR - SR 480 over Missouri River | Richland | 1,056 ft (0.2 mi) | 1968 | 80 |
| Scott ST over Rr | Missoula | 1,024 ft (0.2 mi) | 1979 | 6,636 |
| Old HWY 312 over Yellowstone River 170 | Yellowstone | 1,021 ft (0.2 mi) | 1949 | 4,005 |
| I 90 over Clark Fork River | Missoula | 1,019 ft (0.2 mi) | 1979 | 4,584 |
| State Highway 24 over Ft. Peck Spillway | McCone | 1,017 ft (0.2 mi) | 1937 | 203 |
| I 90 over Clark Fork River | Missoula | 981 ft (0.2 mi) | 1964 | 9,168 |
| 5th AVE S over Clark Fork 085 | Sanders | 979 ft (0.2 mi) | 1975 | 100 |
| S 59 over Yellowstone River | Custer | 976 ft (0.2 mi) | 1957 | 2,949 |
| I 90 over Yellowstone River | Yellowstone | 975 ft (0.2 mi) | 2022 | 14,744 |
| I-90 over Yellowstone River | Yellowstone | 975 ft (0.2 mi) | 2023 | 14,744 |
| S Higgins AVE over Clark Fork R-ped Paths | Missoula | 973 ft (0.2 mi) | 1962 | 11,197 |
| Central AVE over Missouri River-ped Trail | Cascade | 963 ft (0.2 mi) | 1980 | 24,549 |
| S 16 over Missouri River | Richland | 954 ft (0.2 mi) | 1988 | 1,014 |
| S 200 over Clark Fork River | Sanders | 952 ft (0.2 mi) | 1960 | 2,482 |
| US 2 over Kootenai River-rr | Lincoln | 941 ft (0.2 mi) | 1942 | 2,104 |
| Pn Bridge RD over Missouri River | Chouteau | 903 ft (0.2 mi) | 1982 | 39 |
| I 90 over Clark Fork Rvr-rr-local | Mineral | 901 ft (0.2 mi) | 1982 | 3,559 |
| S 253 over Yellowstone River | Prairie | 896 ft (0.2 mi) | 1959 | 441 |
| S 35 over Flathead River | Flathead | 883 ft (0.2 mi) | 1994 | 11,074 |
| I 90 over Clark Fork Rvr-rr-local | Mineral | 880 ft (0.2 mi) | 1982 | 3,559 |
| I 90 over Clark Fork River | Missoula | 878 ft (0.2 mi) | 1964 | 4,584 |
| I 90 over Clark Fork River | Mineral | 866 ft (0.2 mi) | 1981 | 4,088 |
| S Billings BLVD over Yellowstone River | Yellowstone | 860 ft (0.2 mi) | 1972 | 9,226 |
| I 15 over Int Dearborn-missouri R | Cascade | 849 ft (0.2 mi) | 1971 | 2,201 |
| IRR - US 2 over S Fork Flathead River | Flathead | 843 ft (0.2 mi) | 2018 | 8,735 |
| I 15 over Int Dearborn-missouri R | Cascade | 840 ft (0.2 mi) | 1971 | 2,201 |
| N Reserve ST over Clark Fork River | Missoula | 831 ft (0.2 mi) | 1975 | 35,914 |
| US 12 over Yellowstone River | Rosebud | 829 ft (0.2 mi) | 1958 | 722 |
| 7th AVE N over Rr | Hill | 827 ft (0.2 mi) | 1936 | 3,404 |
| I 90 over Clark Fork River | Mineral | 825 ft (0.2 mi) | 1967 | 3,825 |
| I 90 over Clark Fork River | Mineral | 825 ft (0.2 mi) | 1967 | 3,825 |
| I 15 over Missouri River-local | Cascade | 818 ft (0.2 mi) | 1971 | 2,201 |
| I 90 over Clark Fork River | Mineral | 806 ft (0.2 mi) | 1965 | 4,088 |
| Bundy RD over Yellowstone River | Yellowstone | 805 ft (0.2 mi) | 2001 | 87 |
| I 90 over Clark Fork River | Mineral | 800 ft (0.2 mi) | 1966 | 3,825 |
| I 90 over Clark Fork River | Mineral | 800 ft (0.2 mi) | 1960 | 3,825 |
| I 15 over Missouri River-local | Cascade | 791 ft (0.1 mi) | 1971 | 2,201 |
| I 15 over Sep Boulder Ave-rr | Lewis and Clark | 791 ft (0.1 mi) | 2016 | 14,810 |
| I 94 over Int Circle-rr-7m CR | Dawson | 788 ft (0.1 mi) | 1969 | 2,693 |
| Old HWY 10 E over Clark Fk-rr 060 | Mineral | 786 ft (0.1 mi) | 1942 | 140 |
| I 15 over Sep Boulder Ave-rr | Lewis and Clark | 784 ft (0.1 mi) | 2017 | 14,810 |
| I 90 over Int Cyr-clark Fork Rvr | Mineral | 780 ft (0.1 mi) | 1981 | 4,585 |
| I 94 over Int Circle-rr-7m CR | Dawson | 772 ft (0.1 mi) | 1969 | 3,373 |
| I 15 over Sep Missouri Rvr-co RD | Lewis and Clark | 770 ft (0.1 mi) | 1967 | 2,201 |
| I 15 over Sep Missouri Rvr-co RD | Lewis and Clark | 770 ft (0.1 mi) | 1967 | 2,201 |
| Heron RD over Cabinet Gorge Res 049 | Sanders | 767 ft (0.1 mi) | 2017 | 539 |
| I 90 over Int Cyr-clark Fork Rvr | Mineral | 761 ft (0.1 mi) | 1965 | 4,585 |
| I 90 over Clark Fork River | Mineral | 756 ft (0.1 mi) | 1967 | 3,825 |
| I 90 over Clark Fork River | Mineral | 756 ft (0.1 mi) | 1967 | 3,825 |
| US 12 over Little Blackfoot Riv-rr | Powell | 745 ft (0.1 mi) | 2009 | 3,217 |
| I 15 over Rr-missouri River | Cascade | 740 ft (0.1 mi) | 1968 | 2,201 |
| I 15 over Rr-missouri River | Cascade | 738 ft (0.1 mi) | 1968 | 2,201 |
| I 90 over Madison River-rr | Gallatin | 735 ft (0.1 mi) | 1964 | 9,762 |
| I 90 over Yellowstone River | Park | 729 ft (0.1 mi) | 1962 | 6,397 |
| I 90 over Yellowstone River | Park | 729 ft (0.1 mi) | 1962 | 6,397 |
| Conrad DR over Flathead River 013 | Flathead | 726 ft (0.1 mi) | 2009 | 100 |
| Kona Ranch RD over Clark Fork 011 | Missoula | 724 ft (0.1 mi) | 1987 | 100 |
| I 90 over Int W Garrison-rr | Powell | 709 ft (0.1 mi) | 1979 | 5,232 |
| I 90 over Int W Garrisison-rr | Powell | 709 ft (0.1 mi) | 1979 | 5,232 |
| S 80-13th ST over Missouri River | Chouteau | 708 ft (0.1 mi) | 1962 | 930 |
| Myers RD over Yellowstone River | Treasure | 705 ft (0.1 mi) | 1968 | 96 |
| US 191 over Missouri River | Fergus | 697 ft (0.1 mi) | 1959 | 655 |
| California AVE over Kootenai River | Lincoln | 697 ft (0.1 mi) | 1959 | 5,674 |
| S 82 over Flathead River | Flathead | 685 ft (0.1 mi) | 1955 | 8,310 |
| S 446 over Yellowstone River | Rosebud | 683 ft (0.1 mi) | 1970 | 257 |
| Mt 37 Fh 57 over Sutton Creek | Lincoln | 661 ft (0.1 mi) | 1974 | 346 |
| US 287 over Missouri River | Broadwater | 661 ft (0.1 mi) | 2020 | 5,250 |
| IRR - S 382 over Flathead River | Sanders | 653 ft (0.1 mi) | 1965 | 391 |
| Central AVE E over Missouri River | Cascade | 652 ft (0.1 mi) | 1954 | 289 |
| I 15 over Little Prickly Pear CR | Lewis and Clark | 652 ft (0.1 mi) | 1965 | 2,403 |
| Business RTE 90 over Yellowstone River | Park | 641 ft (0.1 mi) | 2013 | 5,141 |
| I 90 over St. Regis Rvr-local RD | Mineral | 637 ft (0.1 mi) | 1979 | 7,448 |
| Old HWY 10 W over Powder River 040 | Prairie | 635 ft (0.1 mi) | 1945 | 507 |
| Old HWY 10 over Bighorn River 126 | Yellowstone | 629 ft (0.1 mi) | 1930 | 100 |
| IRR - S 13 over Missouri River | Roosevelt | 625 ft (0.1 mi) | 1998 | 1,163 |
| US 212 over Powder River | Powder River | 625 ft (0.1 mi) | 1985 | 2,084 |
| I 90 over Madison River-rr | Gallatin | 624 ft (0.1 mi) | 1964 | 9,762 |
| IRR - US 2 over Middle Fork Flathead Riv | Flathead | 623 ft (0.1 mi) | 2002 | 2,025 |
| US 12 over Powder River | Custer | 622 ft (0.1 mi) | 1973 | 552 |
| I 90 over Clark Fork River | Mineral | 620 ft (0.1 mi) | 1960 | 3,719 |
| I 15 over Local-creek-rarus Rr | Silver Bow | 613 ft (0.1 mi) | 1961 | 3,728 |
| Noxon AVE E over Cabinet Gorge Resv 047 | Sanders | 599 ft (0.1 mi) | 1922 | 100 |
| I 15 over Local-creek-rarus Rr | Silver Bow | 598 ft (0.1 mi) | 1961 | 3,728 |
| I 15 over Silverbow Creek-rr | Silver Bow | 598 ft (0.1 mi) | 2018 | 7,379 |
| I 15 over Silverbow Creek-rr | Silver Bow | 598 ft (0.1 mi) | 2019 | 7,379 |
| I 90 over Int E Garrison-rr | Powell | 597 ft (0.1 mi) | 1979 | 5,232 |
| IRR - I 90 over Bighorn River | Big Horn | 593 ft (0.1 mi) | 1971 | 4,258 |
| IRR - I 90 over Bighorn River | Big Horn | 593 ft (0.1 mi) | 1971 | 4,258 |
| I 90 Frontage RD over Bighorn River | Big Horn | 590 ft (0.1 mi) | 2007 | 1,455 |
| I 90 over Int E Garrison-rr | Powell | 581 ft (0.1 mi) | 1979 | 5,232 |
| I 94 over Bighorn River | Yellowstone | 580 ft (0.1 mi) | 1963 | 2,613 |
| I 90 over Yellowstone River | Stillwater | 577 ft (0.1 mi) | 1976 | 5,423 |
| IRR - S 313 over Bighorn River | Big Horn | 575 ft (0.1 mi) | 1958 | 899 |
| S 78 over Yellowstone River | Stillwater | 575 ft (0.1 mi) | 1957 | 5,017 |
| I 15 over Rr-hwy 91- Drainage | Madison | 570 ft (0.1 mi) | 1974 | 1,926 |
| I 94 over Bighorn River | Yellowstone | 570 ft (0.1 mi) | 1978 | 2,613 |
| Musselshell Trl RD over Yellowstone River | Yellowstone | 566 ft (0.1 mi) | 1964 | 265 |
| US 87 over Yellowstone River | Yellowstone | 565 ft (0.1 mi) | 1993 | 23,199 |
| I 15 over Sep Rr | Beaverhead | 560 ft (0.1 mi) | 2016 | 1,771 |
| I 90 over Yellowstone River | Stillwater | 557 ft (0.1 mi) | 1961 | 5,423 |
| Duck Creek RD over Yellowstone River 020 | Yellowstone | 557 ft (0.1 mi) | 1991 | 100 |
| I 90 over Int W Laurel-rr | Yellowstone | 556 ft (0.1 mi) | 2018 | 9,599 |
| Central AVE W over Galt Ave-rr | Cascade | 553 ft (0.1 mi) | 1967 | 6,158 |
| Madison St-us 12 over Clark Fork River | Missoula | 551 ft (0.1 mi) | 1958 | 18,393 |
| US 93 over Bitterroot River | Ravalli | 551 ft (0.1 mi) | 2005 | 14,573 |
| Old US 91 over Missouri River-rr 069 | Cascade | 549 ft (0.1 mi) | 1931 | 316 |
| I 90 over Clark Fork River | Mineral | 544 ft (0.1 mi) | 1976 | 100 |
| Marias Valley RD over Marias River 001 | Toole | 544 ft (0.1 mi) | 1936 | 511 |
| I 15 over Int Spring Creek-rr | Lewis and Clark | 539 ft (0.1 mi) | 1964 | 2,555 |
| I 94 over Powder River | Prairie | 539 ft (0.1 mi) | 1971 | 2,137 |
| Central AVE W over Galt Ave-rr | Cascade | 538 ft (0.1 mi) | 1967 | 6,158 |
| I 15 over Rr-hwy 91-drainage | Madison | 538 ft (0.1 mi) | 1974 | 1,926 |
| I 94 over Powder River | Prairie | 538 ft (0.1 mi) | 1971 | 2,137 |
| I 15 over Missouri River | Cascade | 532 ft (0.1 mi) | 1971 | 2,201 |
| I 15 over Missouri River | Cascade | 532 ft (0.1 mi) | 1971 | 2,201 |
| HWY 287 Bypass over Missouri River 019 | Broadwater | 531 ft (0.1 mi) | 1920 | 178 |
| Millegan RD over Missouri River | Cascade | 530 ft (0.1 mi) | 1983 | 553 |
| I 15 over Int Spring Creek-rr | Lewis and Clark | 529 ft (0.1 mi) | 1964 | 2,555 |
| US 87 over Abandoned Railroad | Chouteau | 527 ft (0.1 mi) | 1974 | 1,727 |
| Buffalo Bridge RD over Flathead River 084 | Lake | 527 ft (0.1 mi) | 1993 | 100 |
| I 15 over Little Prickly Pear CR | Lewis and Clark | 525 ft (0.1 mi) | 1965 | 2,403 |
| IRR BIA RTE 91 over Big Horn River | Big Horn | 524 ft (0.1 mi) | 1970 | 360 |
| Old HWY 10 W over Clark Fork 054 | Mineral | 518 ft (0.1 mi) | 1932 | 356 |
| US 212 over Yellowstone River | Yellowstone | 512 ft (0.1 mi) | 1997 | 12,394 |
| Craig Frontage RD over Missouri River 054 | Lewis and Clark | 506 ft (0.1 mi) | 1933 | 484 |
| 6th ST SW over Sun River | Cascade | 505 ft (0.1 mi) | 1980 | 13,800 |
| Reed Point RD over Yellowstone River 004 | Stillwater | 505 ft (0.1 mi) | 2000 | 175 |
| I 94 over Rr | Prairie | 501 ft (0.1 mi) | 1969 | 1,939 |
| US 12 over Missouri River | Broadwater | 500 ft (0.1 mi) | 1935 | 6,843 |
| S Orange ST over Clark Fork River | Missoula | 496 ft (0.1 mi) | 2003 | 22,608 |
| IRR - S 200 over Jocko River-rr | Lake | 493 ft (0.1 mi) | 1998 | 1,938 |
| Rapelje RD over Sep Rapelje-i 90 | Stillwater | 492 ft (0.1 mi) | 1971 | 453 |
| Bridge ST over Missouri River 062 | Lewis and Clark | 490 ft (0.1 mi) | 2006 | 778 |
| Reserve ST over W Broadway St-rr | Missoula | 489 ft (0.1 mi) | 1998 | 29,572 |
| David Thompson Brg over Kootenai River D/s Dam | Lincoln | 488 ft (0.1 mi) | 1967 | 100 |
| IRR - US 2 over Flathead River | Flathead | 488 ft (0.1 mi) | 1977 | 22,220 |
| I 90 over Blackfoot River | Missoula | 486 ft (0.1 mi) | 2018 | 6,216 |
| I 15 NB over Sun River | Cascade | 484 ft (0.1 mi) | 1966 | 5,254 |
| I 15 SB over Sun River | Cascade | 484 ft (0.1 mi) | 1966 | 5,254 |
| I 15 over Marias River | Toole | 483 ft (0.1 mi) | 1976 | 1,311 |
| I 15 over Marias River | Toole | 483 ft (0.1 mi) | 1976 | 1,311 |
| Sloway Frntge RD E over Abandoned Rr 001 | Mineral | 481 ft (0.1 mi) | 1956 | 100 |
| I 15 over Sep Rr | Beaverhead | 480 ft (0.1 mi) | 1980 | 1,771 |
| I 94 over Rr-highline Canal RD | Yellowstone | 479 ft (0.1 mi) | 1968 | 2,611 |
| S 213 over Rr | Glacier | 474 ft (0.1 mi) | 2012 | 1,321 |
| I 90 over Int W Laurel-rr | Yellowstone | 473 ft (0.1 mi) | 2019 | 9,599 |
| Old Stage Road over Yellowstone River 077 | Park | 471 ft (0.1 mi) | 1980 | 104 |
| RD 552 over Powder River 016 | Powder River | 470 ft (0.1 mi) | 2008 | 47 |
| S 200 over Clark Fork River | Sanders | 469 ft (0.1 mi) | 1996 | 3,009 |
| I 90 over Black Foot River | Missoula | 468 ft (0.1 mi) | 2019 | 6,216 |
| Lozeau Crossovr RD over Clark Fork 045 | Mineral | 463 ft (0.1 mi) | 1944 | 221 |
| No Data Entered over Nezperce Fk | Ravalli | 463 ft (0.1 mi) | 1972 | 10 |
| N Russel Street over Clark Fork River | Missoula | 463 ft (0.1 mi) | 2020 | 23,274 |
| S 41 over Jefferson River | Madison | 462 ft (0.1 mi) | 1992 | 2,195 |
| Petty Creek RD over Clark Fork 008 | Missoula | 457 ft (0.1 mi) | 1964 | 948 |
| S Shiloh RD over Sep I 90 | Yellowstone | 457 ft (0.1 mi) | 1959 | 3,188 |
| Trail Creek RD over Powder River 061 | Custer | 455 ft (0.1 mi) | 1926 | 100 |
| I 90 over St. Regis Rvr-local RD | Mineral | 455 ft (0.1 mi) | 1979 | 7,448 |
| I 90 over Clark Fork River | Missoula | 455 ft (0.1 mi) | 1965 | 10,294 |
| I 90 over Clark Fork River | Missoula | 455 ft (0.1 mi) | 1965 | 10,294 |
| F Bridge RD over Marias River | Toole | 455 ft (0.1 mi) | 1953 | 55 |
| I 15 over Big Hole River | Madison | 452 ft (0.1 mi) | 1973 | 1,926 |
| Rock CR RD over Clark Fk-rr-hwy 106 | Missoula | 450 ft (0.1 mi) | 1972 | 603 |
| US 89 over Yellowstone River | Park | 450 ft (0.1 mi) | 1958 | 2,289 |
| S 200 over Blackfoot River | Missoula | 449 ft (0.1 mi) | 1968 | 4,627 |
| I 15 over Beaverhd R-high Brdg RD | Beaverhead | 448 ft (0.1 mi) | 1981 | 2,185 |
| I 90 over Sep Elizabeth LN | Mineral | 447 ft (0.1 mi) | 1981 | 4,088 |
| I 94 over Rr-highline Canal RD | Yellowstone | 446 ft (0.1 mi) | 1968 | 2,611 |
| I 90 over Sep Elizabeth LN | Mineral | 445 ft (0.1 mi) | 1965 | 4,088 |
| S 200 EB over Blackfoot River | Missoula | 445 ft (0.1 mi) | 1940 | 2,314 |
| S 200 over Blackfoot River | Missoula | 445 ft (0.1 mi) | 1988 | 4,627 |