Yellowstone County Bridge Report Card

Yellowstone County scores 89 out of 100 on BridgeLookup's Bridge Condition Exposure Score, based on FHWA National Bridge Inventory records.

B89 / 100

Local infrastructure snapshot

Yellowstone County, Montana

Yellowstone County has 290 bridges in the National Bridge Inventory, with 7 rated poor and 6 rated scour-critical. Its poor-condition share of 2.4% is at or below the 7.4% statewide average. Poor-condition bridges carry about 26,944 daily vehicle crossings.

290Total Bridges

7Poor (2.4%)

186Fair (64.1%)

6Scour-Critical

Quote-Ready Local Facts

2.4%of county bridges are in poor condition, compared with 7.4% statewide and 6.7% nationally.

26,944daily vehicle crossings are on poor-condition bridges in the county.

6bridges are rated scour-critical, or 2.1% of the county bridge inventory.

Copyable Facts for Reporters

BridgeLookup.com gives Yellowstone County a Bridge Condition Exposure Score of 89/100 (B). The county has 290 bridges in the National Bridge Inventory, including 7 in poor condition and 6 rated scour-critical. Poor-condition bridges carry about 26,944 daily vehicle crossings. Poor condition does not mean unsafe; bridges judged unsafe are closed or restricted by transportation agencies.

Download all county report-card scores as CSV.

How the Score Breaks Down

Factor	Weight	County Value	Penalty
Poor-condition bridge share	40	2.4%	4.8
Poor-condition traffic exposure	25	2.5% of measured traffic	1.8
Scour-critical bridge share	20	2.1%	4.1
Average age vs national baseline	10	45 years vs 48 nationally	0.0
Traffic-data completeness	5	1,093,385 measured daily crossings	0.0

Score = 100 minus weighted penalties. The score is a comparative research signal, not an official safety rating. Read the full methodology.

County Comparisons

County Poor-Condition Share	2.4%
State Poor-Condition Share	7.4%
National Poor-Condition Share	6.7%
County Scour-Critical Share	2.1%
Average Bridge Age	45 years
Poor-Condition Traffic Exposure	26,944 vehicles/day

Bridges to Watch

Busiest Poor-Condition BridgeMontana AVE over U1025-rr — 8,576 vehicles/day Oldest Listed BridgeS 56th ST W over Canyon Creek Ditch 075 — built in 1925 All County BridgesBrowse every bridge record in Yellowstone County.

Top Bridges to Watch in Yellowstone County

Bridge	Reason	Condition	Daily Traffic	Year Built
Old HWY 312 over Yellowstone River 170	Poor condition + traffic exposure	Poor	4,005	1949
Montana AVE over U1025-rr	Poor condition + traffic exposure	Poor	8,576	1960
Montana AVE over U1024-25-rr	Poor condition + traffic exposure	Poor	8,576	1960
S Shiloh RD over Sep I 90	Poor condition + traffic exposure	Poor	3,188	1959
Old US 10 over Big Ditch 051	Poor condition + traffic exposure	Poor	2,489	1932
W I RD over Custer Coulee 098	Poor condition + traffic exposure	Poor	100	1962
Anita Res Acc RD over Anita Dam Spillway	Poor condition + traffic exposure	Poor	10	1937
Inner Belt Loop over Alkali Creek 208	Scour-critical foundation rating	Good	1,178	2014
W M RD over Arrow Creek 099	Scour-critical foundation rating	Fair	164	1975
Canyon Creek RD over Canyon Creek 042	Scour-critical foundation rating	Fair	100	1965

Important safety note

Poor condition does not mean a bridge is unsafe. It means at least one major component has significant deterioration and the bridge is a priority for maintenance, repair, or replacement. Bridges judged unsafe are closed or restricted by transportation agencies.