Porvoo Museum is a history museum occupying the old town hall and a 19th-century merchant's house on the main square. It covers the history of the town from medieval times through the 19th century, with collections of local silver, furniture, textiles, and portraits of the prominent families who made Porvoo a prosperous trading town. Founded in 1897, it is one of the oldest museums in Finland.
The town hall building, a yellow neoclassical structure on the old market square, is a landmark in itself. The museum is small enough to visit in an hour and the collections are genuinely interesting if you have any curiosity about Finnish provincial bourgeois life in the 18th and 19th centuries.