The county says the bridge itself was not damaged.
Thurmont, Md (KM) Roddy Road near the covered bridge will be closed for most of this week,
The Frederick County Office of Highway Operations says the over-height warning portal near the north end of the historic span was struck by a vehicle. Repairs will be made by county staff, and the road is expected to re-open later this week.
The bridge itself was not damaged, officials say.
By Kevin McManus