How to read a lighthouse
A light at sea is a sentence: who I am, how high I stand, how far I can be seen. This is how to read it, with India's own lights as the examples.
Lighthouses
183
on India's coasts and islands, with 214 harbour, breakwater and range lights beside them
Open to visitors
75
named by the ministry in August 2026; 73 are on the map
Farthest listed
32 nautical miles
Dolphin's Nose and Diu Head: about 59 km in clear air
Highest lamp
173 m
Dolphin's Nose, above the sea; the tower itself is 19 m
The coast, drawn by its lights alone
- lighthouse, larger for a longer range
- harbour, breakwater or range light
- open to visitors
What a lighthouse is
“A tower, or substantial building or structure, erected at a designated geographical location to carry a signal light and to assist marine navigation.”
IALA dictionary, the lighthouse authorities' own.
On this map a light is a lighthouse when the List describes a tower that shows 15 nautical miles or more, or when the ministry or the directorate names it. The rest are lesser lights.
Open the mapA light is known by its rhythm
a pattern of light and dark, repeated without end
8 Indian lights over thirty seconds
Each bar is lit; each gap is dark. The letters are how the List of Lights writes it: Fl flashing, (3) in groups of three, W white, 20s the whole pattern repeats every 20 seconds.
Flashing · Fl
“the total duration of light in each period is clearly shorter than the total duration of darkness”
Occulting · Oc
“the total duration of light in each period is clearly longer than the total duration of darkness”
What India's 183 lighthouses do
Nearly all flash: one at a time, or in twos, threes or fours. Two go dark instead, and four have no rhythm in the List.
On the map
½ speed
The map opens at half speed so the rhythms can be read; Real time plays the List's own seconds. A light's card draws its one period on a strip, with a line moving across it.
How far it shows
two limits: the air, and the curve of the earth
The lamp, the sea and a ship's eye
The dotted line is the last straight sight of the lamp over the sea's curve, for an eye 5 m up. A light listed for further than that is seen past it only as a glow in the sky.
Listed range
“its luminous range in a homogeneous atmosphere in which the meteorological visibility is 10 sea-miles”
IALA: nominal range. It is how strong the light is, said as a distance in clear air. Haze shortens it.
Over the curve
“limited only by the curvature of the earth, by refraction of the atmosphere, and by the elevation of the observer and the object or light”
IALA: geographical range. A lamp 25 m up is in view to about 15 nautical miles; one 173 m up, to about 31.
Listed range of the lighthouses, nautical miles
One nautical mile is 1.852 km. 179 of the 183 lighthouses have a range in the List.
Colour, and where it shows
a light can say different things to different bearings
A sector light, from above
“displays a light of different colours and/or rhythms over designated arcs. The colour of the light provides directional information to the mariner.”
The List's remarks for this one: “W. 057°-217°, R.-247°, W.-260°, R.-290°, W.-009°.”
Colour sectors
13
Indian lights whose remarks give arcs of red, green or white. The map draws each arc in its colour.
Arc of visibility
31
lights listed as visible only over part of the compass; the land hides the rest. The map lights only that arc.
The towers
drawn from the List's own words for each
To one scale, beside a person and a coconut palm
The tallest of each shape among the lighthouses, and one of the shortest.Three lighthouses: the tallest, one of middling height and one of the shortest. Shape, colours and bands are as the List describes each tower; how wide it is for its height is ours.
Years on record, by decade
A year is on record for 85 of the 183. It may be the year a light was first shown at the place, not the year of the tower standing there now; where two records differ the card shows both.
By year, on the map
The map's By year opens these towers in a row on one ground line, oldest first, each to scale. Tap one to go to it.
Open the mapVisiting one
what the ministry and the directorate have published
Developed for visitors
75
lighthouses, named state by state in the ministry's reply to the Rajya Sabha. PIB, 11 Aug 2026
Lighthouse museums
7
- Chennai
- Mahabalipuram
- Alappuzha
- Kannur
- Muttom
- Dwarka
- Gopnath
the same release
Hours in print
4
- Anjengo 15.00–17.00
- Aguada 10.00–17.30, 19.30–20.30
- Alang 15.00–17.30
- Kelshi Anjarle 15.00–17.30
The directorate's portal prints visiting hours for these only. For the rest, the card links the lighthouse's own page.
What the directorate's pages list most
- children play area 36
- parking 27
- garden 16
- public amenities 13
- washroom 11
- equipment 11
Counted over the 67 lighthouse pages joined to a light on the map. Tickets are booked on the directorate's portal, lighthouse.nic.in.
Not placed
2
- Kuthenkuli Lighthouse
- Tajpur Lighthouse
of the 75: no light in the List, and no usable map point on the portal. The Data page says why for each.
Who keeps the lights
Directorate General of Lighthouses and Lightships
“a subordinate office under the Ministry of Ports, Shipping and Waterways”, with its headquarters at Noida and the coast divided into nine districts:
- Gandhidham
- Jamnagar
- Mumbai
- Goa
- Cochin
- Chennai
- Visakhapatnam
- Kolkata
- Port Blair
It keeps the general aids under the Marine Aids to Navigation Act 2021; ports and state maritime boards keep the local ones. Its own introduction
The List of Lights
Publication 112 of the US National Geospatial-Intelligence Agency, the volume that carries India's coasts: one entry a light. Public domain. The rhythm, height and range of every light on the map are its.
Not for navigation
This is a picture of the lights, drawn from a list whose newest correction for these coasts is notice 34 of 2023. A light built or changed since may be missing. Mariners use the current charts and notices.