The urban area is relatively hilly, the district Bergslagen on the highest point of the city is the historical center of Ronneby. The river Rönnebyån passes through the city and surrounds the old town center from three sides.
On the north side of the historical center is a waterfall, which was used to operate water mills since the Middle Ages. The former house of the miller is now home to the local history museum and cultural center Möllebackagården.
Not far from the waterfall lies the Heliga Kors Kyrka from the 12th century. The large church is known for its medieval limestone paintings and the beautiful brickwork of the arches, as well as the scene of a bloodbath in 1564. Even today, the marks of the battle axes of Swedish troops can be seen on the church doors.
Ronneby became famous in Europe through the health resort Ronnebybrunn. With the discovery of an iron-rich spring in 1705 the development of a spa town began, whose great heyday lasted from about 1870 to the mid-1930s. Even today, the more than three hundred years old Ronneby Brunnspark is regularly used for numerous events and recreational activities. It is still one of the most beautiful parks Europe.