St. Mary's County Bridge Report Card
St. Mary's County scores 84 out of 100 on BridgeLookup's Bridge Condition Exposure Score, based on FHWA National Bridge Inventory records.
St. Mary's County, Maryland
St. Mary's County has 40 bridges in the National Bridge Inventory, with 2 rated poor and 0 rated scour-critical. Its poor-condition share of 5.0% is above the 4.6% statewide average. Poor-condition bridges carry about 8,160 daily vehicle crossings.
Quote-Ready Local Facts
Copyable Facts for Reporters
BridgeLookup.com gives St. Mary's County a Bridge Condition Exposure Score of 84/100 (B). The county has 40 bridges in the National Bridge Inventory, including 2 in poor condition and 0 rated scour-critical. Poor-condition bridges carry about 8,160 daily vehicle crossings. Poor condition does not mean unsafe; bridges judged unsafe are closed or restricted by transportation agencies.
How the Score Breaks Down
| Factor | Weight | County Value | Penalty |
|---|---|---|---|
| Poor-condition bridge share | 40 | 5.0% | 10.0 |
| Poor-condition traffic exposure | 25 | 3.3% of measured traffic | 2.5 |
| Scour-critical bridge share | 20 | 0.0% | 0.0 |
| Average age vs national baseline | 10 | 56 years vs 48 nationally | 3.4 |
| Traffic-data completeness | 5 | 248,702 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 | 5.0% |
| State Poor-Condition Share | 4.6% |
| National Poor-Condition Share | 6.7% |
| County Scour-Critical Share | 0.0% |
| Average Bridge Age | 56 years |
| Poor-Condition Traffic Exposure | 8,160 vehicles/day |
Bridges to Watch
Top Bridges to Watch in St. Mary's County
| Bridge | Reason | Condition | Daily Traffic | Year Built |
|---|---|---|---|---|
| Md 5 over Hilton Run | Poor condition + traffic exposure | Poor | 8,010 | 1936 |
| Cornfield Harbor D over Point Lookout Creek | Poor condition + traffic exposure | Poor | 150 | 1970 |
| Md 4 over Kingston Creek | High traffic | Fair | 26,801 | 1980 |
| Md 5 over ST Marys River | High traffic | Fair | 22,642 | 1955 |
| Md 5 over Mcintosh Run | High traffic | Fair | 22,220 | 1935 |
| Md 5 over Branch Of Mcintosh Run | High traffic | Good | 22,220 | 2017 |
| Md 5 over Town Run | High traffic | Fair | 21,360 | 1990 |
| Md 5 over Glebe Run | High traffic | Fair | 12,500 | 1955 |
| Md 5 over Eastern Branch | High traffic | Fair | 10,000 | 2016 |
| Pegg Road over Branch Jarboesville Run | High traffic | Fair | 9,574 | 1990 |
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.