Merrimack County Bridge Report Card

Merrimack County scores 67 out of 100 on BridgeLookup's Bridge Condition Exposure Score, based on FHWA National Bridge Inventory records.

D67 / 100

Local infrastructure snapshot

Merrimack County, New Hampshire

Merrimack County has 326 bridges in the National Bridge Inventory, with 27 rated poor and 10 rated scour-critical. Its poor-condition share of 8.3% is above the 7.5% statewide average. Poor-condition bridges carry about 244,642 daily vehicle crossings.

326Total Bridges

27Poor (8.3%)

153Fair (46.9%)

10Scour-Critical

Quote-Ready Local Facts

8.3%of county bridges are in poor condition, compared with 7.5% statewide and 6.7% nationally.

244,642daily vehicle crossings are on poor-condition bridges in the county.

10bridges are rated scour-critical, or 3.1% of the county bridge inventory.

Copyable Facts for Reporters

BridgeLookup.com gives Merrimack County a Bridge Condition Exposure Score of 67/100 (D). The county has 326 bridges in the National Bridge Inventory, including 27 in poor condition and 10 rated scour-critical. Poor-condition bridges carry about 244,642 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	8.3%	16.6
Poor-condition traffic exposure	25	8.1% of measured traffic	6.1
Scour-critical bridge share	20	3.1%	6.1
Average age vs national baseline	10	59 years vs 48 nationally	4.6
Traffic-data completeness	5	3,029,532 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	8.3%
State Poor-Condition Share	7.5%
National Poor-Condition Share	6.7%
County Scour-Critical Share	3.1%
Average Bridge Age	59 years
Poor-Condition Traffic Exposure	244,642 vehicles/day

Bridges to Watch

Busiest Poor-Condition BridgeI-89 over South Street — 46,612 vehicles/day Oldest Listed BridgeNew Market Road over Warner River — built in 1840 All County BridgesBrowse every bridge record in Merrimack County.

Top Bridges to Watch in Merrimack County

Bridge	Reason	Condition	Daily Traffic	Year Built
I-89 over South Street	Poor condition + traffic exposure	Poor	46,612	1959
Us202 over Nhrr Constitution Av.	Poor condition + traffic exposure	Poor	45,555	1958
I-393 US 4 Us202 over Fort Eddy RD	Poor condition + traffic exposure	Poor	40,527	1980
Nh 9(loudon Road) over Merrimack River	Poor condition + traffic exposure	Poor	23,721	1966
I-393 US 4 Us202 over I-93	Poor condition + traffic exposure	Poor	22,391	1958
I-89 SB over Turkey Pond	Poor condition + traffic exposure	Poor	20,703	1959
I-89 NB over Turkey Pond	Poor condition + traffic exposure	Poor	20,387	1959
Nh104 over Smith River	Poor condition + traffic exposure	Poor	2,913	1940
Nh 11 over Nhrr(abd)	Poor condition + traffic exposure	Poor	2,674	1929
Nh 11 over Sucker Brook	Poor condition + traffic exposure	Poor	2,674	1929

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.