Penobscot CountyMaine
North Penobscot, Maine
1 high-hazard dam is rated in poor or unsatisfactory condition. 10 of its 38 inventoried bridges are rated poor (26%, against 15% statewide).
- Live · as of Sep 11, 2026
- 9 public sources · method
- ← All towns
Median depth to bedrock
28 ft
middle half 18–39 ft · 79 logs
Bridges rated poor
10
of 38 inventoried · 2 closed
Poor high-hazard dams
1
National Inventory of Dams
Mapped landslides
1
USGS inventory points
01 · Dams & disasters
1 high-hazard dam needs work
FEMA Public Assistance is reported by county, so the figure below is Penobscot County-wide context, not a North Penobscot number.
| Dam | Condition | Built |
|---|---|---|
| Grand Lake (Matagamon)Penobscot River | Poor | 1941 |
High hazard potential means failure would probably cost lives — it rates the consequences, not the dam’s condition.
FEMA Public Assistance, Penobscot County
$84.9M
Federal share obligated across 255 projects in 4 declared disasters since 2010. The largest category is emergency protective measures (91%); roads & bridges took $1.1M.
02 · Bridges
10 of 38 bridges are rated poor — above the Maine rate of 15%
Every highway bridge and large culvert in the 2025 National Bridge Inventory that stands inside North Penobscot. Median age 26 years; 2 posted for weight; 2 closed.
26% good, 26% poor
FHWA good / fair / poor rating — the lowest of deck, superstructure, substructure or culvert.
- Good10 · 26%
- Fair18 · 47%
- Poor10 · 26%
Structures by decade built
n = 38 structuresSource: FHWA National Bridge Inventory 2025
▸ Show the numbers▾ Hide the numbers
| Built | Structures |
|---|---|
| 1930s | 1 |
| 1960s | 6 |
| 1970s | 3 |
| 1990s | 2 |
| 2000s | 19 |
| 2010s | 4 |
| 2020s | 3 |
The poor-rated bridges
| Carries | Over | Built | Daily traffic |
|---|---|---|---|
| BIA ROUTE 1530 | JOHNNY AYRES BROOK | 2012 | 30 |
| BIA ROUTE 440posted | SAM AYERS STREAM | 1998 | 20 |
| BIA ROUTE 449 | E BRANCH SEBOEIS STREAM | 2003 | 20 |
| BIA RTE 1531 | MATTAMISCONTIS STREAM | 2004 | 15 |
| SWIFT BROOK ROAD | SANDBANK STREAM | 2000 | 10 |
| SHERMAN LUMBER COM | SEBOEIS RIVER | 2000 | 10 |
| ORIN FALLS ROADclosed | KATAHDIN BROOK | 2000 | 5 |
| SWIFT BROOK ROAD | EAST BRANCH OF PENOBSCOT | 2000 | 2 |
| EAST BRANCH ROAD | UNNAMED STREAM | 2000 | 2 |
| EAST BRANCH ROADclosed | BIG SPRING BROOK | 2000 | 2 |
03 · Ground
Rock turns up a median 28 ft down
From 79 depth-to-rock records inside North Penobscot (Maine Geological Survey wells database). Logs cluster where people drill wells and bore for roads, so treat this as the town’s pattern, not a site answer.
Half of North Penobscot's logs reach rock between 18 and 39 ft
Depth to bedrock: 10th–90th percentile whisker, middle-half box, median tick; dashed line = Maine median.
median 28 ftME 15 ft
02040 ft
n = 79 logsSource: Maine Geological Survey wells database
▸ Show the numbers▾ Hide the numbers
| Depth to rock (ft) | Logs |
|---|---|
| 0–5 | 2 |
| 5–10 | 8 |
| 10–20 | 13 |
| 20–50 | 43 |
| 50–100 | 11 |
| 100+ | 2 |
Rock within 10 ft
15%
of logs (40% across Maine). Shallow rock means ledge in excavations, refusal for driven piles and rock anchors rather than soil nails; deep ground means taller shoring and more groundwater. 14% of logs here go past 50 ft.
Mapped landslides
1
1 translational. Inventory points from the USGS U.S. Landslide Inventory; many are prehistoric slides mapped from lidar.
04 · Next door
North Penobscot and the 20 towns that border it
A dash means no data for that layer, not zero.
| Town | Poor bridges | Rock depth |
|---|---|---|
| North Penobscot, ME | 10 / 38 | 28 ft |
| Northeast Piscataquis, ME | 2 / 13 | 41 ft |
| Howland, ME | 3 / 9 | 36 ft |
| Penobscot Indian Island, ME | 2 / 8 | — |
| Medway, ME | 3 / 7 | 25 ft |
| Sherman, ME | 0 / 7 | 9 ft |
| South Aroostook, ME | 3 / 6 | 16 ft |
| Millinocket, ME | 2 / 4 | 40 ft |
| Patten, ME | 1 / 4 | 8 ft |
| Chester, ME | 0 / 3 | 26 ft |
| Mount Chase, ME | 0 / 3 | 14 ft |
| Stacyville, ME | 1 / 2 | 5 ft |
| Central Aroostook, ME | 0 / 2 | 16 ft |
| Maxfield, ME | 0 / 1 | 57 ft |
| Seboeis, ME | 0 / 1 | 38 ft |
| Hersey, ME | 0 / 1 | — |
| Moro, ME | 0 / 1 | — |
| Lake View, ME | — | 62 ft |
| Woodville, ME | — | 12 ft |
| East Millinocket, ME | — | — |
| Northwest Aroostook, ME | — | — |
Where these numbers come from
Method, sources & caveats
North Penobscot is the Census county subdivision 2301952710 (Penobscot County). Every record is placed here by its coordinates, not by the place name the source uses.
- Towns are Census county subdivisions: cities, towns, plantations, and Maine/New Hampshire unorganized territories and townships. Every record is placed in a town by its coordinates (point-in-polygon), not by the source's own place label — so a bridge in Roxbury counts for Boston and a well in 'North Waltham' counts for Waltham.
- Bridges: FHWA NBI 2025, highway structures ≥ 20 ft including large culverts. 'Poor' is FHWA's good/fair/poor rating (lowest of deck, superstructure, substructure or culvert ≤ 4). Percent-poor is shown only for towns with at least 5 structures.
- Depth to bedrock is the median of driller- and boring-reported depths in the town, shown only where at least 10 logs exist. Water-well logs over-sample rural lots and hilltops; one town median never describes a particular site.
- Bedrock depths use the same state databases and filters as the Bedrock & soils module (bedrock wells and borings that reached rock, 0 < depth ≤ 400 ft, exact re-filings dropped), but every log is placed in a town by its coordinates rather than the driller's town field, so town counts can differ slightly between the two pages. Connecticut and Rhode Island have no statewide public well-log database with depths.
- Dams: only high-hazard-potential dams whose latest condition assessment is Poor or Unsatisfactory are counted (live NID). Connecticut and Rhode Island assessments may lag.
- FEMA Public Assistance dollars are federal share obligated for disasters declared since 2010, reported by county — they are county context, not a town figure.
- Grant awards are Massachusetts only (EEA Dam & Seawall program, MVP Action grants, CZM Coastal Resilience). Other states' programs are not yet included.
- Ground-related permit counts cover only the municipal portals the pipeline reads (Boston, Cambridge, Somerville, Worcester, Framingham, Providence, Portsmouth, Hartford and a few others) — an absent count means 'not covered', not zero.
- Data as of
- Sep 11, 2026
- Generated
- Sep 11, 2026
- Records
- 367,748
- Refresh
- Live pull · weekly
- U.S. Census Bureau cartographic boundary files — county subdivisions (2024, 1:500k)Public domain
- FHWA National Bridge Inventory (2025 delimited files)Public domain
- USACE National Inventory of DamsPublic domainHigh-hazard dams rated Poor or Unsatisfactory (live NID).
- USGS U.S. Landslide InventoryPublic domain
- MassGIS / Massachusetts Geological Survey — Bedrock Data PointsPublic recordBorings and well logs that reached rock (MassDEP well drillers, USGS, MWRA, MassDOT…); seismic/HVSR and map-derived shallow-bedrock/outcrop points excluded.
- NH DES Water Well Inventory, Maine Geological Survey Wells Database, Vermont DEC well recordsPublic recordBedrock wells only; driller-reported depth to bedrock / overburden thickness.
- OpenFEMA Public Assistance Funded Projects Details (v2)Public domain
- MA EEA / CZM grant awards — Dam & Seawall, MVP Action, CZM Coastal ResiliencePublic record
- Municipal open-data permit portals (Boston, Cambridge, Somerville, Providence, Portsmouth, others)Public recordOnly permits flagged as ground-related (retaining walls, excavation, foundations) are counted.
Published by Earth Support Corp as a public resource. Regional statistics for planning and curiosity. They are not an engineering report, a bid recommendation or a statement about any particular site, firm or project. Spot an error? Tell us and we will correct it. Full method: methodology.