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Treholmen Lighthouse

Oc (3) White/Red/Green 10s🇳🇴Ørland, NOOperational

Location & Light Range

About Treholmen Lighthouse

Treholmen Lighthouse is a white, square tower with a lantern and gallery, standing 6 meters tall on the north point of Treholmen island. This structure is located about 8 kilometers west of Lysøya and is 2.5 kilometers from the nearest port, Lysoysund. Its focal height reaches 8 meters, and it emits a light that shows three occultations of white, red, or green every 10 seconds. The lighthouse's light has a geographic range of 9.7 nautical miles. While the island site is open to visitors, the tower itself is closed to the public.

Why it matters: This lighthouse provides specific directional guidance, changing its light color to assist vessels in avoiding hazards and maintaining correct courses in the waters west of Lysøya.

Light & Optic

Characteristic Signature
Oc (3) White/Red/Green 10s
Flash Type
Occulting
Light Color
White/Red/Green
Flash Count
3 flashes
Interval
10s
Raw Code
Oc(3) WRG 10s
Focal Height
8m
Geographic Range
9.7NM

Location

City
Ørland
Country
🇳🇴Norway
Region
Trøndelag
Sea Region
Located on the north point of Treholmen, a small island about 8 km west of Lysøya.
Latitude
63.8965°
Longitude
9.7767°

References & Identifiers

Nearest Port
Lysoysund(2.5 km)
Admiralty No.
L1602
NGA No.
8288

Tower & Structure

Tower Height
6m
Tower Shape
square
Tower Color
white

Structure: square tower with lantern and gallery, painted white; lantern roof painted red

Visiting

Open to public
Site open, tower closed

Nearby Vessels

Flag
Type
Name
Dist.
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Frequently Asked Questions

How do mariners identify Treholmen Lighthouse at night?+
Treholmen displays the characteristic Oc (3) White/Red/Green 10s — 3 white/red/green flashes every 10 seconds. Each lighthouse has a unique flash pattern published in the List of Lights, allowing mariners to positively identify it and distinguish it from other navigation aids in the area. The white/red/green color may indicate a specific sector or warning zone.
Which ports and harbors does Treholmen Lighthouse guide vessels into?+
Treholmen Lighthouse assists vessels approaching 5 nearby ports. The closest is Lysøysund at 2.4 NM to the ESE. Other ports served include Vallersund (2.9 NM SSW), Valsneset (6 NM SW), Bjugn (8.2 NM S), Herfjord (9.2 NM NE). Mariners should consult the relevant chart for full approach and pilotage information.
Is Treholmen Lighthouse still active and maintained?+
Yes, Treholmen Lighthouse is currently operational. It is actively maintained and continues to emit its characteristic light signal for marine navigation. Most modern lighthouses are automated and monitored remotely by the national maritime authority.
What shipping routes pass near Treholmen Lighthouse?+
Treholmen Lighthouse is located within the Baltic Sea trade route — a vital shipping corridor for trade between Scandinavian, German, Polish, and Baltic state ports. This makes it an important navigation reference for commercial shipping traffic in the region.
How can I track vessels near Treholmen Lighthouse?+
You can track vessels near Treholmen Lighthouse in real time using MarineRadar. The platform shows live AIS positions of ships in the area, including vessel name, type, flag, speed, and course. Use the "Track Vessels Nearby" button on this page to open the live map centered on this lighthouse.