Kastellet 2026 Guide: The Star Fortress & Windmill (Free Entry)

TLDR: Kastellet (The Citadel) is one of the best-preserved star fortresses in Northern Europe, located near the Little Mermaid. It is an active military site but functions as a public park. Admission is completely free, and the gates are open daily from 06:00 to 22:00.

Today, Kastellet it is a beloved green space for joggers and history buffs alike. Famous for its red barracks, historic windmill, and peaceful ramparts, it offers a quiet escape in the city center.

This guide covers the best walking route, opening hours, and what you can see inside for free.

What is the story behind Kastellet?

Construction of Kastellet began under King Christian IV in 1626, with an advanced coastal post. The star-shaped citadel as it stands today was commissioned by King Frederick III and built by Dutch engineer Henrik Rüse between 1662 and 1665.

Over the years, Kastellet played an important role in Danish military history. During the 19th century, it served as a barracks for the Danish army, and during World War II, it was occupied by German forces. Today, it is still an active military facility and is used by the Danish Defence Intelligence Service, the Home Guard and the Judge Advocate Corps.

Despite military presence at Kastellet, it is widely visited by tourists and locals, as the area is also serving as a public park.

What to see inside Kastellet?

Kastellet is a popular tourist attraction, not only for its historical significance but also for its beautiful architecture and scenic surroundings. Read about some of the notable features and attractions of Kastellet below.

• The Windmill: One of the most iconic features of Kastellet is its windmill, which dates back to the 1840s. The windmill was used to grind grain for the soldiers stationed at Kastellet and was in use until 1903.
• The Citadel Church: The Citadel Church is a beautiful baroque-style church located within the walls of Kastellet. It was built in the 1704 and is still used for religious services today.
• The Commander's House: The Commander's House is a historic building that was once the residence of the commanding officer at Kastellet. Today, the building services as a information center for the Monument to Denmark's International Activities after 1948.
• The Bastions: Kastellet is surrounded by five bastions, each of which has its own distinctive shape and features. Visitors can walk along the ramparts and enjoy stunning views of Copenhagen Harbour and the surrounding area.
• The Park: Kastellet is also home to a large and beautiful park, which is a popular spot for picnics, strolls, and outdoor activities. The park is home to a number of statues and monuments. ‍
• The Ramparts: Walk along the top of the star-shaped walls for views of the harbor and the Royal Yacht.

What are the opening hours at Kastellet?

The rules and opening hours of Kastellet is:

• Opening Hours: Daily 06:00 – 22:00 (Gates close automatically).
• Grass: You are generally not allowed to walk on the grass inside the ramparts (keep to the cobblestones).
• Jogging: Allowed on the ramparts, but respectful behavior is required as it is an active military base.

Is Kastellet free?

Yes, entering Kastellet is 100% free. You do not need a ticket to walk through the gates, stroll on the ramparts, or see the windmill.

• Note: The buildings (barracks, offices) are active military sites and are generally closed to the public, except for the church during specific service times.

How to get to Kastellet?

Kastellet is located in the Østerbro district, right next to the Langelinie waterfront.

• From the Little Mermaid: It is a 5-minute walk. Enter through the "Norwegian Gate."
• Metro/Train: The nearest stop is Østerport Station (5-10 minute walk).
• Walking: It is a scenic 15-minute walk north from Amalienborg Palace along the waterfront.

Is it worth visiting Kastellet in Copenhagen?

Kastellet is a unique and fascinating destination in Copenhagen, with a rich history and a range of interesting things to see. Whether you're interested in military history, architecture, or just looking for a beautiful place to explore, Kastellet is well worth a visit.

So why not take a stroll around the fortress and soak up some of Copenhagen's rich history and culture?

What else can I do in Copenhagen?

Once you've enjoyed the expansive green spaces of Kastellet , Copenhagen still has so much more to offer.

• Head to the Statens Museum for Kunst (National Gallery of Denmark), which is centrally located and houses a vast collection spanning centuries, offering a truly diverse artistic journey.
• Just a short distance away, you can step back in time at the historic Rosenborg Castle and wander through its beautiful King's Garden, the oldest royal garden in central Copenhagen.
• For a unique and perhaps more reflective experience, visit Assistens Cemetery . This peaceful green space serves as the final resting place for Danish luminaries like Hans Christian Andersen and Søren Kierkegaard, and locals often use it for quiet walks.

You can also read our full guide to the top attractions in Østerbro.

To enhance your exploration, I highly recommend downloading the StoryHunt app. It acts as your personal audio guide, filling your ears with engaging stories about both Copenhagen's top attractions and its many hidden gems as you discover them. Download StoryHunt for Android and iOS here.