Md 121 over Little Seneca Lake
FairMontgomery County, Maryland · 0.39 Mile North of Md 117 · Structure no. 100000150021010
- Built
- 1984
- 41 years old
- Condition
- Fair
- inspected June 2024
- Type
- Girder and Floorbeam System
- Steel Continuous
- Length
- 537 ft
- 3 main spans
- Daily traffic
- 3,571
- 2009 count
- Owner
- State
- State Highway Agency
About this bridge
Md 121 over Little Seneca Lake is a steel continuous girder and floorbeam system carrying Md 121 over Little Seneca Lake in Montgomery County, Maryland. It was built in 1984, so it is 41 years old, younger than the Maryland average of 52.6 years.
The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.
It carries about 3,571 vehicles a day, roughly 8% of them trucks, projected to reach 5,357 by 2029. The structure is 537 ft (163.7 m) long and 47 ft wide. If it were closed, the detour would be 8.7 mi (14 km).
Location
No coordinates are recorded for this structure.
Condition and inspection
The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 7 Good | Some minor problems. |
| Superstructure | 7 Good | Some minor problems. |
| Substructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Channel and channel protection | 8 Very Good | No problems noted. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was Md 121 over Little Seneca Lake built?
It was built in 1984, making it 41 years old in 2025.
What condition is Md 121 over Little Seneca Lake in?
The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in June 2024.
How much traffic does Md 121 over Little Seneca Lake carry?
About 3,571 vehicles per day (2009 count), of which roughly 8% are trucks.
How long is Md 121 over Little Seneca Lake?
The structure is 537 ft (163.7 m) long with a longest span of 200 ft (61 m) and a deck 47 ft wide.
Who owns Md 121 over Little Seneca Lake?
It is owned by the State Highway Agency.