Bridge conditions in Grafton County, New Hampshire

547 inventoried bridges · 43 rated poor · 2025 National Bridge Inventory

United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled August 20, 2026

43 of the 547 bridges the federal inventory lists in Grafton County are rated poor; the rest split 262 good and 242 fair.

43 of the 547 bridges in Grafton County, New Hampshire, are rated in poor condition (7.9%) in the 2025 National Bridge Inventory, as of August 20, 2026.
262 bridges (47.9%) are rated good and 242 (44.2%) fair.
The median Grafton County bridge was built in 1968.
The busiest poor-rated bridge is I-89 NB over Connecticut River Necrr (built 1966), carrying about 22,288 vehicles a day.

Good 47.9% · Fair 44.2% · Poor 7.9% of 547 bridges

Bridges rated poor

Every bridge in the county with a poor rating, busiest first. Poor means a major component is rated 4 or lower on FHWA's 0-9 scale; it is a repair flag, not a closure notice.

Bridge	Built	Vehicles/day	Condition
I-89 NB over Connecticut River Necrr	1966	22,288	Poor
I-89 SB over Connecticut River Necrr	1966	21,268	Poor
US 4 Mechanic St over Mascoma River	1977	12,803	Poor
Nh 12A over Nhrr	1949	9,117	Poor
NH112 Kancamagus over Pemigewasset River	1933	6,210	Poor
Nh 3A over Newfound River	1924	5,690	Poor
NH120 Park Lot Ped over Nhrr(abd)	1969	5,317	Poor
Nh 3A over Newfound River	1949	2,878	Poor
Nh 49 over Mad River	1979	2,828	Poor
US 3 over Lost River	1931	2,784	Poor
East Thetford Road over Connecticut River	1937	2,160	Poor
School Street over Ammonoosuc River	1960	2,087	Poor
Nh 49 over Pemigewasset River	1928	1,917	Poor
Nh 18 over Connecticut River	1934	1,508	Poor
NH118 over Indian River	1948	1,436	Poor
US 3 over Bog Brook	1929	1,193	Poor
NH142 over Ammonoosuc River	1927	1,167	Poor
Dorchester Road over Grant Brook	1952	1,132	Poor
Trues Brook Road over Bloods Brook	1952	1,089	Poor
Nh 25 over Oliverian Brook	1960	1,072	Poor
Nh 25A over Brackett Brook	1929	826	Poor
Nh 25A over Baker Pond Brook	1929	826	Poor
NH175 over Pemigewasset River	1939	674	Poor
Potato Road over Indian River	1930	655	Poor
Lafayette Road over Ham Branch	1920	436	Poor
Sand Hill Road over Baker River	1928	410	Poor
Grist Mill Hill Rd over Indian River	1956	365	Poor
Washburn Road over Patten Brook	1950	289	Poor
Archertown Road over Jacobs Brook	1930	244	Poor
Eastside Road over Martins Brook	1940	219	Poor
Great Brook Road over Great Brook	1936	107	Poor
Cole Hill Road over Fowler River	1930	96	Poor
River Road over Clay Brook	1900	96	Poor
Perch Pond Road over Ryan Brook	1940	96	Poor
Plains Road over Mill Brook	1975	96	Poor
Breezy Hill Road over Salmon Hole Brook	1975	96	Poor
High Bridge Road over Archertown Brook	1940	96	Poor
Crane Hill Road over Gale River	1928	96	Poor
Tunnel Brook Road over Wild Ammonoosuc River	1900	52	Poor
Fdr 304 over Little River	1975	50	Poor
Nfsr XH22 over Hubbard Brook	1961	50	Poor
Fdr 29 over Walker Brook	1975	50	Poor
Fish Hatchery Road over Patch Brook	1930	45	Poor

Busiest bridges in the county

Bridge	Built	Vehicles/day	Condition
I-89 NB over Plaza Connector Road	2012	28,690	Fair
I-89 Nh 10 over Brook Atv Trail	1959	25,062	Fair
I-89 Nh 10 NB over Truck Road Mascoma River	1966	23,084	Fair
I-89 NB over US 4 Nh 10	1966	22,727	Good
I-89 NB over Connecticut River Necrr	1966	22,288	Poor
I-89 Nh 10 SB over US 4	1966	21,937	Good
I-89 SB over Connecticut River Necrr	1966	21,268	Poor
I-89 SB over US 4 Nh 10	1966	19,997	Fair
I-89 SB over Truck Road Mascoma River	1966	19,997	Fair
I-89 NB over Nh 12A	2012	19,291	Good

Source: FHWA National Bridge Inventory, 2025. Counts cover inventoried highway bridges over 20 feet; ratings are reported by the state DOT.

All of New Hampshire: New Hampshire bridge conditions by county · every download on the data page.

Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.