Middlesex CountyMassachusetts
Cambridge, Massachusetts
Bedrock sits a median 57 ft down across 130 logs, deeper than the Massachusetts median of 24 ft. 7 of its 37 inventoried bridges are rated poor (19%, against 9% statewide).
- Live · as of Sep 11, 2026
- 9 public sources · method
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Median depth to bedrock
57 ft
middle half 21–77 ft · 130 logs
Bridges rated poor
7
of 37 inventoried
State resilience grants
$1.0M
1 award on file
Construction projects
99
median $2.8M · public bid results
01 · Ground
Deep ground: 60% of logs go past 50 ft before rock
From 130 depth-to-rock records inside Cambridge (MassGIS / MGS borings & well logs). Logs cluster where people drill wells and bore for roads, so treat this as the town’s pattern, not a site answer.
Half of Cambridge's logs reach rock between 21 and 77 ft
Depth to bedrock: 10th–90th percentile whisker, middle-half box, median tick; dashed line = Massachusetts median.
median 57 ftMA 24 ft
050100 ft
n = 130 logsSource: MassGIS / MGS borings & well logs
▸ Show the numbers▾ Hide the numbers
| Depth to rock (ft) | Logs |
|---|---|
| 0–5 | 16 |
| 5–10 | 3 |
| 10–20 | 12 |
| 20–50 | 21 |
| 50–100 | 62 |
| 100+ | 16 |
Rock within 10 ft
22%
of logs (23% across Massachusetts). 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. 60% of logs here go past 50 ft.
02 · Bridges
7 of 37 bridges are rated poor — above the Massachusetts rate of 9%
Every highway bridge and large culvert in the 2025 National Bridge Inventory that stands inside Cambridge. Median age 41 years; 3 posted for weight.
30% good, 19% poor
FHWA good / fair / poor rating — the lowest of deck, superstructure, substructure or culvert.
- Good11 · 30%
- Fair19 · 51%
- Poor7 · 19%
Structures by decade built
n = 37 structuresSource: FHWA National Bridge Inventory 2025
▸ Show the numbers▾ Hide the numbers
| Built | Structures |
|---|---|
| pre-1910 | 4 |
| 1910s | 1 |
| 1920s | 3 |
| 1930s | 1 |
| 1940s | 1 |
| 1950s | 6 |
| 1980s | 5 |
| 1990s | 6 |
| 2000s | 10 |
The poor-rated bridges
| Carries | Over | Built | Daily traffic |
|---|---|---|---|
| ST 28 CHAS R DM RD | CHARLES RIVER | 1906 | 28,188 |
| US 3 /ST2&16/ALWFposted | TR RED LINE | 1983 | 25,732 |
| ST 3 NB/MEMORL DR | CHARLES RIVER | 1956 | 18,750 |
| US 3 MEMORIAL DR | BROOKLINE ST | 1940 | 18,503 |
| FIRST STposted | BROAD CANAL | 1924 | 15,388 |
| LAND BLVDposted | BROAD CANAL | 1956 | 12,579 |
| HURON AVE | OTHER GREENWAY M/U PATH | 1985 | 7,100 |
03 · Money & permits
99 construction projects on file, median $2.8M — above the state's $1.5M
| Project | Year | Award |
|---|---|---|
| Cambridge Reservoir Dam/Hobbs Brook Gatehouse and Outlet Culvert Repairs | FY2024 | $1.0M |
Public construction projects
99
Median estimated value $2.8M, middle half $500K–$20.0M, against $1.5M across Massachusetts. Capped total $1.6B (each project counted at no more than $100M). Public bid records compiled June 2026, heavy on 2021–22 — a sample, not an annual market.
Ground-related permits in open data
10
Permits in the city’s open-data portal that mention retaining walls, excavation or foundations. Only a handful of portals are read, so this counts what is published, not everything built.
04 · Dams & disasters
Middlesex County has drawn $656M in federal disaster repair since 2010
FEMA Public Assistance is reported by county, so the figure below is Middlesex County-wide context, not a Cambridge number.
FEMA Public Assistance, Middlesex County
$656M
Federal share obligated across 1,729 projects in 12 declared disasters since 2010. The largest category is emergency protective measures (97%); roads & bridges took $1.2M.
05 · Next door
Cambridge and the 5 towns that border it
A dash means no data for that layer, not zero.
| Town | Poor bridges | Rock depth |
|---|---|---|
| Cambridge, MA | 7 / 37 | 57 ft |
| Boston, MA | 41 / 404 | 92 ft |
| Somerville, MA | 5 / 42 | 27 ft |
| Arlington, MA | 3 / 9 | 10 ft |
| Watertown, MA | 0 / 4 | 51 ft |
| Belmont, MA | 0 / 2 | 22 ft |
Where these numbers come from
Method, sources & caveats
Cambridge is the Census county subdivision 2501711000 (Middlesex County). Every record is placed here by its coordinates, not by the place name the source uses. Construction-project figures come from Massachusetts public bid results, published as town-level counts, medians and capped totals (n ≥ 10).
- 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.