A rural municipality, not a single resort
Sund occupies part of Åland’s main island, east of Mariehamn. It is a municipality of dispersed settlements rather than a compact town, and its 1,018 residents were counted across the municipality on 31 December 2025. That figure helps put the visitor sites in perspective: Kastelholm and Bomarsund are prominent destinations, but they are only two places within a lived-in rural area whose everyday rhythm includes homes, farms, roads, schools and municipal services. Sund’s Swedish-language public administration is part of Åland’s wider Swedish-speaking setting; Swedish is also the language used by the municipality, the regional visitor service and the local museum material consulted for this guide.
The landscape is shaped by the sea even where a visitor is travelling on land. Roads cross inlets and low wooded ground, while the route between the west of Sund and Bomarsund links a medieval administrative centre with a nineteenth-century military project. That contrast is the municipality’s most compelling thread: power here was once expressed through a castle controlling waterways, and later through a Russian fortress intended to command the Baltic approaches. Both projects left ruins and collections of evidence, not a mythical ancient foundation. Sund is best understood through these documented layers and the ordinary rural communities between them.
Church and castle: the medieval record
Sund’s stone church is among Åland’s oldest surviving medieval buildings. Current archaeological work places its construction broadly between 1250 and 1275; the dating remains a research conclusion rather than a precise year preserved in a founding document. It is a useful starting point for understanding why this part of the island mattered before modern roads: church, settlement and navigable waters formed a connected landscape.
Kastelholm Castle is the island’s only medieval castle. The Åland Museum identifies its first known written mention in an estate inventory from 1388. That is a firm documentary point, but it does not tell us the exact year construction began. The fortress grew and changed through several phases and became an administrative centre during the period when Åland belonged to the Swedish realm. Its role declined in the seventeenth century, and fires and abandonment left the structure in ruins. Today, visitors can read those changes in the surviving walls and courtyards rather than being asked to accept a tidy legend about a single founder or a dramatic overnight origin.
The castle is part of a small cultural cluster. Next door, Jan Karlsgården gathers historic Åland farm buildings and shows how a rural household was arranged and worked in the nineteenth century. Vita Björn, the former county jail, is now a prison museum. Together the three sites make a visit more than a castle stop: they set administrative power beside ordinary work and the history of confinement. Opening periods are seasonal, so check the museum’s current calendar before travelling.
Bomarsund and Prästö: an unfinished imperial project
Bomarsund belongs to a much later and more violent chapter. After Sweden ceded Finland and Åland to Russia in 1809, Russian authorities planned a major fortress on the islands. Construction proceeded during the first half of the nineteenth century, and a settlement grew around the military works. The stronghold was still incomplete when British and French forces attacked it during the Crimean War in 1854. The fortress was surrendered and subsequently destroyed; fragments of walls, towers and related structures are now spread across a broad outdoor heritage area. The visitor centre adds maps, interpretation and audiovisual material to a landscape that can otherwise be difficult to read at first glance.
Across the water, Prästö preserves another part of the same story. Its walking trail passes the cemeteries of several religious communities associated with the garrison population, as well as the site of the military hospital and surviving Russian-era telegraph buildings. The marked route is listed at about 5.5 kilometres and two to three hours. It is graded easy, although two short rocky sections mean it is not stroller-friendly. This is a place for respectful walking: gravestones and burial grounds are historical evidence and still places of remembrance.
The outdoor fortress remains can be visited year-round, while the visitor centre and nearby seasonal food service operate on a more limited calendar. A beach and walking routes make it possible to spend more time in the area, but services should not be assumed to be open outside the warmer months. Check current opening dates and trail notices before setting out.
What visitors can do today
Kastelholm is Sund’s most concentrated visitor area. In addition to the castle, farm museum and prison museum, the surrounding cultural landscape has a restaurant and café, a distillery, a guest harbour, Ålands Golf Club across the narrow waterway, and a nine-hole disc-golf course. This mix gives visitors options beyond history: a meal, an overnight stop by boat, a round of golf or a short outdoor activity can turn a museum visit into a fuller day. These are individual services with their own hours and seasons, so check directly before relying on them.
Sund’s municipal website also lists the services that support residents rather than tourists: childcare, school, library, social care, waste management, water and sewer information, roads and rescue services. For a visitor, these details matter most when planning a longer stay or travelling with family; for the municipality, they are a reminder that the historical sites sit inside a working community rather than an open-air theme park. Visitors should plan food and fuel before leaving Mariehamn or the larger service centres if they are travelling outside the main tourist season.
Getting there and planning a day
Mariehamn is the nearest city and the natural starting point for most trips. By road, the journey follows Åland’s fixed-island network through Godby toward Kastelholm, then continues east to Bomarsund and Prästö. Visit Åland describes Bomarsund as roughly 33 kilometres from Mariehamn, with Kastelholm on the way; distances depend on the exact starting point and route. The corridor is also served by regional buses, but services vary by day and season. Use Åland’s current journey planner and the transport authority’s timetable before choosing a departure, and check any connection required for the return.
A practical first visit can pair Kastelholm’s museum sites with lunch or a café stop, then leave time for a walk at Bomarsund. A longer day can add the Prästö trail, but its length and rocky passages deserve more than a quick detour. Cyclists can follow the main-island route between the historic areas, while drivers have more flexibility to reach separate towers and trailheads. Sund rewards a slower itinerary: the church, the castle, the farm buildings, the fortress ruins and the cemeteries reveal different communities and different kinds of power, all within one small Åland municipality. Check schedules, opening hours and trail conditions on the day of travel.
Sund in three films: Kastelholm, its museums and Bomarsund
Fly relaxed takes a very different approach: this short cinematic drone film concentrates on the exterior of Kastelholm Castle. Its value is visual, giving the viewer an elevated sense of the building within its setting. It does not try to explain the castle's political history, the church nearby or the museum area, so it works best as a visual preview alongside the Åland Museum's interpretation. Check the official site for access, seasonal opening dates and guided visits.
Panzerphantom's drone view moves the focus east to Bomarsund. The film is specifically presented as an aerial view of the fortress ruins, so it offers a way to read the scattered remains as a landscape rather than as a single standing building. It is a visual record, not an account of the 1854 battle and not a guide to the visitor centre. Pair it with the centre's current information before deciding which walking routes and displays to include.