About this place
Nestled between the granite cliffs of Hammerknuden and the sea, Hammersø is Denmark’s northernmost and highest natural lake, a place of quiet reflection surrounded by dramatic scenery. The lake lies just inland from the rugged coastline near Sandvig and Hammerhavn, formed in a deep, glacial basin carved into the island’s granite bedrock. Its dark, mirror-like surface perfectly reflects the surrounding cliffs and heather slopes, creating one of the most serene and photogenic landscapes on Bornholm.
The atmosphere here shifts with the light. On calm mornings, the water is still as glass, reflecting the sky and cliffs in flawless symmetry. In the evening, golden light filters over the ridge of Hammerknuden, turning the granite warm and soft. When mist rolls down from the high ground, the lake becomes mysterious and almost alpine in mood. Despite its proximity to some of Bornholm’s most visited sights — Hammershus, Opalsøen, and Hammerhavn — Hammersø feels remarkably peaceful, a natural pause in the drama of the island’s north.
A narrow path circles the lake, winding through birch, pine, and heather. From the trail, you can look up to the granite ridges above or catch glimpses of the Baltic beyond. For photographers, it’s a place of contrasts: still water and rugged cliffs, reflection and solidity, intimacy and vastness. In many ways, Hammersø captures the essence of Bornholm itself — compact yet full of depth, shaped by both fire and ice, and illuminated by an ever-changing northern light.
Best time to visit
- Early morning for calm reflections and mist.
- Sunset for golden tones on the cliffs.
- Autumn for deep color contrasts and atmospheric light.
Practical tips
- Parking near Hammerhavn or Opalsøen; short walk to the lake.
- The circular path around the lake is easy and well-marked (1.5 km).
- Best light in low sun or overcast weather for reflections.
- Combine with Hammershus Slotsruin, Opalsøen, and Hammerodde Fyr for a full northern Bornholm circuit.
Golden Hour & Blue Hour
00:32
Morning Nautical twilight Start
01:53
Morning Civil twilight Start
01:12
Morning Blue hour Start
02:43
Morning Sunrise Start
02:48
Morning Golden hour Start
18:16
Evening Golden hour End
19:14
Evening Sunset Start
20:45
Evening Blue hour End
20:04
Evening Civil twilight End
21:25
Evening Nautical twilight End
Times calculated from coordinates using suncalc.
Current weather

13°C
clear sky
- Feels like
- 13°C
- Humidity
- 89%
- Wind speed
- 6.5 m/s
- Wind direction
- SW (242°)
- Sunrise
- 02:42
- Sunset
- 19:13
Hourly forecast
- Feels like:
- 13°C
- Humidity:
- 89%
- Wind speed:
- 4 (Moderate breeze)
- Wind direction:
- SW
- Cloud cover:
- 7%
- Dew point:
- 11.2°C
Photography tips
- The mirror-like reflections of cliffs and sky on the lake’s surface.
- Warm evening light over Hammerknuden.
- Misty mornings and subtle color gradients in calm weather.
- Textures of granite, heather, and forest mirrored in water.
- Minimalist compositions emphasizing stillness and symmetry.
Hiking tips
- Hammersø loop: 1.5 km gentle walk with continuous lake and cliff views.
- Hammerknuden ridge trail: 5–6 km route above the lake with panoramic vistas.
- Hammershus–Hammersø trail: 3–4 km linking two of Bornholm’s key landmarks.
- Terrain: rocky but well-maintained; easy to moderate difficulty.
Routes
Hikes & rides from here
View on Hammershus – Hammershus Ruins roundtrip from Vang
- Distance
- 16.6 km
- Ascent
- 221 m
- Descent
- 221 m
- Duration
- 4h 45m
This circular route from Vang takes you through the wildest stretch of Bornholm — the granite plateau of Hammerknuden, where the wind is a constant presence and the landscape carries something ancient and unyielding. The route is demanding without being dramatic: nearly seventeen kilometres of endlessly shifting terrain — rocky paths, wooded valleys, open heath — where the elevation doesn't so much accumulate as keep asking for more. This is a walk for people who enjoy a full day on their feet and aren't particularly in a hurry to arrive anywhere.
Early on, the path dips into shadow at [pissebaekken], a small waterfall tucked into a deep gorge between the cliffs — one of those places you'd nearly miss if you didn't know to look. From there the landscape opens toward [hammerso], the quiet lake wedged between granite and sky, and just beyond it the surprisingly emerald water of [opalso-lake], which has an almost otherworldly quality in the hard northern light. The route eventually pulls toward the tip of the island: at [hammerodde-fyr] a small lighthouse stands out on the headland, and at [hammer-odde] itself you feel the land simply run out — granite blocks tumbling straight into the Baltic, with nothing beyond them.
The return leg passes [hammershus-slotsruin], the vast castle ruin perched high on a granite spur above the sea. Photographically, this is a place that rewards patience: the walls read differently as the light turns, and the combination of weathered stone, open sky and coastline in the distance gives you a great deal to work with. Those cycling the route should expect rough sections that require walking — though that feels fitting here. Hammerknuden is not a place that adjusts itself to you.
Hammer So round trip
- Distance
- 5.7 km
- Ascent
- 64 m
- Descent
- 70 m
- Duration
- 1h 33m
The circular walk around Hammersø is one of those routes that doesn't wear you out but settles you instead. The path winds through the granite northern tip of Bornholm, where the landscape feels more open and raw than the rest of the island — less forested, more exposed to wind and light. The elevation changes are modest, the surface alternates between dirt tracks and bare rock outcroppings, and the distance is short enough to move through comfortably at your own pace. Well suited to anyone who prefers a quieter tempo, or for an afternoon when the light is already falling at a lower angle.
The lake itself — [hammerso] — is both the starting point and the anchor of the entire route. Surrounded by granite hills and dense scrub, it has an unexpectedly still quality for such an open stretch of country. The water mirrors the sky in a way that shifts markedly with the weather: grey and heavy under cloud cover, almost metallic when the sun sits low. Those who look closely at the route will also discover [opalso-lake] — the Opal Lake — a smaller, deeper body of water that owes its name to the strikingly green tint of the water. It sits tucked away, and it's precisely that offhandedness that makes it worth finding.
The route is compact enough for a morning loop, but it does ask for some attention to the light — northern Bornholm carries something of a Scandinavian island about it, with a sky that shifts character quickly. Photographically, the reflections on the water and the texture of the granite are the most reliable constants; you don't need to go looking for the image, it simply waits for the right moment.
Passes by
Hammershus Castle Ruins – Hammershus Castle Ruins loop from Sandlinien
- Distance
- 7.4 km
- Ascent
- 97 m
- Descent
- 99 m
- Duration
- 2h 3m
This loop around the northern tip of Bornholm begins gently and reveals itself slowly. The terrain is granite heathland — rough enough to hold your interest, open enough that your thoughts can wander. After a short walk, Hammershus Castle Ruin comes into view: a fortress that doesn't merely sit on a hill, but on a granite headland above the Baltic Sea, as if the island itself decided to plant something permanent here. Most of the walls are gone, but what remains carries weight — not dramatic, just old and indifferent to the centuries that have passed over it. Walking among the remnants isn't a tourist obligation but an invitation to look: at the water below, at the light falling differently on stone than on grass.
From the ruin, the path turns inland, toward Hammersø, Denmark's northernmost lake. The lake sits wedged between granite ridges and has a self-contained quality — it seems simply to exist, with no particular need for visitors. A little further on, deeper into the granite interior, lies Opalsøen. The water holds a green tint that can feel almost unreal, ringed by boulders and quiet trees. This is not a place that asks for attention; you need to pause a moment before you understand what you're seeing.
The route suits those who walk unhurriedly and like to look — no hill training, no technical ground, just a walk with character. Two hours is manageable, but there's more than enough reason to take longer over less distance. It's the kind of loop you can set out on without a plan and still come back feeling that something was seen.
Passes by

