Photographs from the nomination case file, National Park Service records.
Ponakin Bridge
Listed on the National Register of Historic Places in
1979. A historic map-sheet match is not published yet. The record needs a coordinate-quality review before it can be joined to a sheet boundary.
From the record
one of 500 National Register listings in Worcester County · listed in 1979 · category: Structure · one of 1 National Historic Landmarks in Worcester County.
National Register reference number.79000378- the number the National Park Service assigned this property when it was listed, and the key its nomination file is catalogued under at the National Archives.
Fires near this property
136 since 2002
Regional context, not property-specific
evidence. The
federal wildfire occurrence database
lists 136 fires within 5 miles of Ponakin Bridge between
2002 and 2020, burning about 2,731 acres in total. None started naturally. 2 were recorded as arson.
Distance is straight-line from the map coordinates, so a fire counted
here may appear on a neighbouring settlement's page as well.
Reported cause
Fires
Debris and open burning
60
Missing data/not specified/undetermined
36
Recreation and ceremony
17
Smoking
15
Equipment and vehicle use
4
Arson/incendiarism
2
Misuse of fire by a minor
2
The most recent of
them, most recent first, with the day each was reported and the service
that recorded it.
Regional context, not property-specific
evidence. Museums hold 2,152 specimens
collected within 10 miles of Ponakin Bridge between 1859 and
1974: 1,244 Animalia, 545 Plantae, 343 Fungi, 10 Unrecorded, 9 Chromista, 1 Protozoa. 12 distinct Species records are shown.
Collected by A. B. Seymour, A. C. Gibson, A. Ferrett and others. Each is a
physical object with a catalogue
number, and each entry opens the museum's record. This is what was
collected and kept, not a survey of what lives here - nothing can be
concluded from a species being absent.
Regional context, not property-specific
evidence. The federal mineral resources record lists
13 workings within 5 miles of Ponakin Bridge: 6 past producers, 5 producers, 1 prospect, 1 unknown.
5 still produce. What was taken out: Sand and Gravel, Construction, Stone, Crushed/Broken, Iron, Zinc. Distance is straight-line from the
map coordinates, so a quarry counted here may appear on a neighbouring
settlement's page as well.
Regional context, not property-specific
evidence. The National Weather Service names
Lancaster, the town this property stands in, in 8 storm reports between 2005 and 2026: 6 thunderstorm wind, 1 hail, 1 funnel cloud.
No death or injury is recorded in these reports. Each account below is quoted exactly as the forecast office
filed it, from the NOAA Storm Events Database, and each date
opens the federal record of that event.
1 paper published in this town,
digitised by the Library of Congress and free to read: 0 issues,
0 pages. Every page is searchable, so a name or a street can be
looked for directly in what the town printed about itself at the time.
No historic map-sheet match is published
for this property yet. That does not mean no map exists. This record needs
a coordinate-quality review before it can be joined to a sheet boundary.
Browse the county's mapped places while that work is
pending.
From the nomination file
1,649 words on record
When this property was proposed for the
National Register, someone wrote the case for it: what the building is,
and why it matters. That document is a federal record in the public domain.
It is quoted below word for word, never summarised. The text was read off the scanned case file by machine, so the
occasional stray character is the recogniser's and the 1970s
typewriter's.
Description of the property
The Ponakin Bridge is a single span Post through truss constructed in 1871. The bridge serves automobile traffic crossing the north branch of the Nashua River in Lancaster. Originally on the main route from Lancaster to Lunenburg, the bridge is now on a winding country road. It is now approximately 400 feet from a by-pass highway constructed in 1965. The eight truss paneled structure has a span of 100 feet and width of 20 feet. The vertical end posts are riveted in sections. The bridge is typical of Post trusses with pinned end diagonals in compression and diagonal dual eye bars extending two panels in tension. Secondary tension rods running between the dual eye bolts extend across one panel.
Struts connecting each side hip are riveted; top lateral diagonal cross bars provide additional bracing. Floor construction consists of three inch deck planking supported by tranverse cross timbers atop wood stringers which in turn rest on riveted cross floor beams. Floor beams are attached at the panel points. Abutments are 20' granite blocks.
Statement of significance
/ARCHITECT Watson Manufacturing Company The Ponakin Bridge possesses integrity of location, design, setting, materials, and workmanship and is associated with major transportation routes and the development of Lancaster. The bridge also possesses significance in being the only remaining pure version of a Post truss known to the Historic American Engineering Record. In 1871 the town of Lancaster contracted with Watson Manufacturing Company, Builders of Patterson, New Jersey to construct a new bridge replacing the last in a series of of wooden bridges that had been there since the seventeenth century. That year the Ponakin Bridge was built for the sum of $5981 following the design of Simeon S. Post which was patented c. 1866. S.S.
Post was a well known New Hampshire born civil engineer "whose work in addition to bridge design and building included surveys and construction of railroads, particularly the New York and Erie. He was the originator of the system of railroad baggage checking universally adopted and drew the first design for making railroad time tables. He was also a founding member of the original (1852) American Society of Civil Engineers."1 The Post truss is distinguished by compression members that incline toward the center of the bridge. The Post truss bridge was a major bridge form in the second half of the nineteenth century and was the most frequently used bridge form for the transcontinental rallroad.
Other important Post truss bridges include the Union Pacific Railroad's crossing of the Missouri River at Omaha. was the largest on the line. The Missouri River crossing of the Missouri-Kansas-Texas Railroad was also a Post patented bridge with a span of 256'. Despite the truss' popularity, The Ponakin and the nearby Atherton Bridges (NR-eligible) are the only known surviving examples in the country.
Quoted from the National Register nomination
for reference 79000378, 8 pages, held by the National Archives in Record
Group 79. See the
catalogue record.
Listed places nearby
6 within 8 miles
Other National Register properties close
enough to walk or drive between, ordered by distance from this one. Both
positions come from the same geocoding pass that matched these properties
to their map sheets.
Listing record. National Park Service National Register of Historic Places, listed-properties dataset, current to 2026-05-22.
Map join. Address geocoded through the United States Census geocoder, then tested against the published boundary of every sheet in the USGS Historical Topographic Map Collection.
How this page is made. Listing fields come from federal records; map-sheet coverage is a labelled coordinate-to-boundary calculation, not a source-field claim.
Wildfire. Short, Karen C. 2022. Spatial wildfire occurrence data for the United States, 1992-2020 [FPA_FOD_20221014]. 6th Edition. Fort Collins, CO: Forest Service Research Data Archive. https://doi.org/10.2737/RDS-2013-0009.6 Collected with United States Government funding and usable without additional permissions or fees.
Specimens. Global Biodiversity Information Facility (GBIF), https://www.gbif.org/. Only records licensed CC0 or CC BY are used. Records licensed CC BY-NC are excluded because this site carries advertising. Images are checked individually and any whose licence is non-commercial, no-derivatives or unreadable is refused.
Mines and quarries. USGS Mineral Resources Data System (MRDS) https://mrdata.usgs.gov/mrds/ A work of the United States government, no copyright under 17 U.S.C. 105.
Storms. NOAA National Centers for Environmental Information, Storm Events Database https://www.ncei.noaa.gov/stormevents/ A work of the United States government, no copyright under 17 U.S.C. 105. Narratives are quoted verbatim from the National Weather Service report and are not edited or summarised.
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