12 lakes tracked ·
4 with a current elevation reading ·
USGS Water Services + USACE CWMS Data
Connecticut has 12 lakes and reservoirs tracked here — 4 with a current elevation reading, from USGS Water Services and USACE CWMS Data. Sort the table by level, storage, %-full, or trend, then open any lake for its full elevation-with-datum, trend sparkline, storage, and source-and-vintage stamp. Figures are provisional readings for reference — not for navigation or safety decisions.
Statewide totalsConnecticut · USGS + USACE
Lakes tracked
12
4 report a current pool-elevation reading; the rest report storage only.
With elevation reading
4
With %-full figure
0
All Connecticut lakes
Every lake tracked in Connecticut. Click a column heading to sort, or filter by name. Elevation lakes
are listed before storage-only lakes; a missing figure always shows "not reported," never an estimate.
Connecticut lakes, elevation lakes first, by name.
Data: USGS Water Services (waterservices.usgs.gov) and USACE CWMS Data (cwms-data.usace.army.mil), retrieved 2026-08-31. Both public domain (a work of the U.S. Government, 17 U.S.C. §105).
Every Connecticut lake in detail
Each lake tracked in Connecticut has its full record here — current reading, recent
trend, and the dam behind it where the National Inventory of Dams has one. Use the table above
to jump to a lake, or read straight through.
Colebrook Dam
USACE · reading Aug 22, 2026, 1:15 PM (UTC+00:00)
Pool elevation
687.52 ft
Datum NGVD29
% of conservation pool full
Not reported
Storage
33,362 acre-ft
Recent trend
↓Falling
−1.7 ft over the trend window
Colebrook Dam is held back by Colebrook River Dam , a concrete gravity structure, resisting the reservoir by its own weight alone , standing 223 ft high and running 0 ft along its crest , built across WEST BRANCH FARMINGTON RIVER in Litchfield County , near COLEBROOK . It was completed in 1969 , and is owned by USACE - New England District , to a design credited to USACE.
Its recorded primary purpose is flood risk reduction — the pool is drawn down between storms so there is empty space waiting for the next flood, which is why this level can fall in dry weather and climb sharply after rain. Its spillway is ungated: once the pool reaches the crest, water leaves on its own and the operator cannot hold it back. NID classes it high hazard potential. That describes what a failure would cost downstream — loss of life would be expected — and says nothing about how likely a failure is, or what condition the dam is in. National Inventory of Dams record CT00506 — U.S. Army Corps of Engineers, public domain.
Hancock Brook Dam is held back by Hancock Brook Dam , an earthfill embankment, holding the pool back by sheer mass and an impervious core rather than by the strength of concrete , standing 35 ft high and running 2,300 ft along its crest , built across HANCOCK BROOK in Litchfield County , near WATERBURY . It was completed in 1966 , and is owned by USACE - New England District , to a design credited to CENAE.
Its recorded primary purpose is flood risk reduction — the pool is drawn down between storms so there is empty space waiting for the next flood, which is why this level can fall in dry weather and climb sharply after rain. Its spillway is ungated: once the pool reaches the crest, water leaves on its own and the operator cannot hold it back. NID classes it high hazard potential. That describes what a failure would cost downstream — loss of life would be expected — and says nothing about how likely a failure is, or what condition the dam is in. National Inventory of Dams record CT00507 — U.S. Army Corps of Engineers, public domain.
Northfield Brook Dam is held back by Northfield Brook Dam , a concrete gravity structure, resisting the reservoir by its own weight alone , standing 111 ft high and running 810 ft along its crest , built across NORTHFIELD BROOK in Litchfield County , near THOMASTON . It was completed in 1965 , and is owned by USACE - New England District , to a design credited to CENAE.
Its recorded primary purpose is flood risk reduction — the pool is drawn down between storms so there is empty space waiting for the next flood, which is why this level can fall in dry weather and climb sharply after rain. Its spillway is ungated: once the pool reaches the crest, water leaves on its own and the operator cannot hold it back. NID classes it high hazard potential. That describes what a failure would cost downstream — loss of life would be expected — and says nothing about how likely a failure is, or what condition the dam is in. National Inventory of Dams record CT00505 — U.S. Army Corps of Engineers, public domain.
West Thompson Dam is held back by West Thompson Dam , a concrete gravity structure, resisting the reservoir by its own weight alone , standing 70 ft high and running 2,550 ft along its crest , built across QUINEBAUG RIVER in Windham County , near PUTNAM . It was completed in 1965 , and is owned by USACE - New England District .
Its recorded primary purpose is flood risk reduction — the pool is drawn down between storms so there is empty space waiting for the next flood, which is why this level can fall in dry weather and climb sharply after rain. Its spillway is ungated: once the pool reaches the crest, water leaves on its own and the operator cannot hold it back. NID classes it high hazard potential. That describes what a failure would cost downstream — loss of life would be expected — and says nothing about how likely a failure is, or what condition the dam is in. National Inventory of Dams record CT00502 — U.S. Army Corps of Engineers, public domain.
Black Rock Dam is held back by Black Rock Dam , a rockfill embankment — quarried rock placed in compacted layers around a sealing core , standing 130 ft high and running 933 ft along its crest , built across BRANCH BROOK in Litchfield County , near WATERBURY . It was completed in 1971 , and is owned by USACE - New England District , to a design credited to CENAE.
Its recorded primary purpose is flood risk reduction — the pool is drawn down between storms so there is empty space waiting for the next flood, which is why this level can fall in dry weather and climb sharply after rain. Its spillway is ungated: once the pool reaches the crest, water leaves on its own and the operator cannot hold it back. NID classes it high hazard potential. That describes what a failure would cost downstream — loss of life would be expected — and says nothing about how likely a failure is, or what condition the dam is in. National Inventory of Dams record CT00508 — U.S. Army Corps of Engineers, public domain.
East Branch Dam is held back by East Branch Flood Control Dam , an earthfill embankment, holding the pool back by sheer mass and an impervious core rather than by the strength of concrete , standing 92 ft high and running 700 ft along its crest , built across EAST BR NAUGATUCK RIVER in Litchfield County , near TORRRINGTON , and is owned by Connecticut DEEP .
Its recorded primary purpose is flood risk reduction — the pool is drawn down between storms so there is empty space waiting for the next flood, which is why this level can fall in dry weather and climb sharply after rain. NID classes it high hazard potential. That describes what a failure would cost downstream — loss of life would be expected — and says nothing about how likely a failure is, or what condition the dam is in. Its most recent condition assessment was satisfactory — no deficiencies recognised for expected loading. National Inventory of Dams record CT00498 — U.S. Army Corps of Engineers, public domain.
Hall Meadow Dam is held back by Hall Meadow Brook Flood Control Dam , an earthfill embankment, holding the pool back by sheer mass and an impervious core rather than by the strength of concrete , standing 75 ft high and running 1,200 ft along its crest , built across HALL MEADOW BROOK in Litchfield County , near TORRINGTON . It was completed in 1962 , and is owned by Connecticut DEEP .
Its recorded primary purpose is flood risk reduction — the pool is drawn down between storms so there is empty space waiting for the next flood, which is why this level can fall in dry weather and climb sharply after rain. NID classes it high hazard potential. That describes what a failure would cost downstream — loss of life would be expected — and says nothing about how likely a failure is, or what condition the dam is in. Its most recent condition assessment was satisfactory — no deficiencies recognised for expected loading. National Inventory of Dams record CT00497 — U.S. Army Corps of Engineers, public domain.
Hop Brook Dam is held back by Hop Brook Dam , a rockfill embankment — quarried rock placed in compacted layers around a sealing core , standing 89 ft high and running 520 ft along its crest , built across HOP BROOK in New Haven County , near NAUGATUCK . It was completed in 1968 , and is owned by USACE - New England District .
Its recorded primary purpose is flood risk reduction — the pool is drawn down between storms so there is empty space waiting for the next flood, which is why this level can fall in dry weather and climb sharply after rain. Its spillway is ungated: once the pool reaches the crest, water leaves on its own and the operator cannot hold it back. NID classes it high hazard potential. That describes what a failure would cost downstream — loss of life would be expected — and says nothing about how likely a failure is, or what condition the dam is in. National Inventory of Dams record CT00504 — U.S. Army Corps of Engineers, public domain.
Mad River Dam is held back by Mad River Flood Control Dam , an earthfill embankment, holding the pool back by sheer mass and an impervious core rather than by the strength of concrete , standing 178 ft high and running 940 ft along its crest , built across MAD RIVER in Litchfield County , near WINCHESTER . It was completed in 1963 , and is owned by Connecticut DEEP .
Its recorded primary purpose is flood risk reduction — the pool is drawn down between storms so there is empty space waiting for the next flood, which is why this level can fall in dry weather and climb sharply after rain. NID classes it high hazard potential. That describes what a failure would cost downstream — loss of life would be expected — and says nothing about how likely a failure is, or what condition the dam is in. Its most recent condition assessment was satisfactory — no deficiencies recognised for expected loading. National Inventory of Dams record CT00500 — U.S. Army Corps of Engineers, public domain.
Mansfield Hollow Dam is held back by Mansfield Hollow Dam , a concrete gravity structure, resisting the reservoir by its own weight alone , standing 78 ft high and running 14,050 ft along its crest , built across NACHAUG RIVER in Windham County , near WILLIMANTIC . It was completed in 1952 , and is owned by USACE - New England District , to a design credited to CENAE.
Its recorded primary purpose is flood risk reduction — the pool is drawn down between storms so there is empty space waiting for the next flood, which is why this level can fall in dry weather and climb sharply after rain. Its spillway is ungated: once the pool reaches the crest, water leaves on its own and the operator cannot hold it back. NID classes it high hazard potential. That describes what a failure would cost downstream — loss of life would be expected — and says nothing about how likely a failure is, or what condition the dam is in. National Inventory of Dams record CT00503 — U.S. Army Corps of Engineers, public domain.
Sucker Brook Dam is held back by Sucker Brook Flood Control Dam , standing 68 ft high and running 1,160 ft along its crest , built across SUCKER BROOK in Litchfield County , near WINCHESTER . It was completed in 1970 , and is owned by Connecticut DEEP .
Its recorded primary purpose is flood risk reduction — the pool is drawn down between storms so there is empty space waiting for the next flood, which is why this level can fall in dry weather and climb sharply after rain. NID classes it high hazard potential. That describes what a failure would cost downstream — loss of life would be expected — and says nothing about how likely a failure is, or what condition the dam is in. Its most recent condition assessment was satisfactory — no deficiencies recognised for expected loading. National Inventory of Dams record CT00499 — U.S. Army Corps of Engineers, public domain.
Thomaston Dam is held back by Thomaston Dam , a rockfill embankment — quarried rock placed in compacted layers around a sealing core , standing 137 ft high and running 2,000 ft along its crest , built across NAUGATUCK RIVER in Litchfield County , near THOMASTON . It was completed in 1960 , and is owned by USACE - New England District , to a design credited to CENAE.
Its recorded primary purpose is flood risk reduction — the pool is drawn down between storms so there is empty space waiting for the next flood, which is why this level can fall in dry weather and climb sharply after rain. Its spillway is ungated: once the pool reaches the crest, water leaves on its own and the operator cannot hold it back. NID classes it high hazard potential. That describes what a failure would cost downstream — loss of life would be expected — and says nothing about how likely a failure is, or what condition the dam is in. National Inventory of Dams record CT00501 — U.S. Army Corps of Engineers, public domain.