The town of Olsberg was founded as part of the municipal reorganisation of the state of North Rhine-Westphalia on 1 January 1975 through the merger of the town of Bigge-Olsberg, which had existed since 1969, and the municipalities of Antfeld, Assinghausen, Bruchhausen, Brunskappel, Elleringhausen, Elpe, Helmeringhausen, Wiemeringhausen and Wulmeringhausen from the Bigge district and the municipality of Gevelinghausen from the Bestwig district. The town belongs to the Hochsauerland district.

On 31 December 2022, Olsberg had 14,668 inhabitants with main residence and 15,344 inhabitants including secondary residence. The urban area is 117 km² in size. Around 63% is forested.

Olsberg lies in a wide valley surrounded by a ring of wooded hills. In this valley basin, the young Ruhr, which flows in from the south, turns its course to the west and forms the lowest point of the urban area at 313 metres above sea level when it leaves the urban area in the Bigge district. In a northerly direction, the mountains in Antfelder Forst rise up to 560 metres above sea level from the Ruhr valley, while in a south-easterly direction - just 10 km away - the highest mountain in North Rhine-Westphalia, Langenberg, reaches 843 metres. Olsberg is therefore the only municipal unit in the west of Germany whose topographical relief has an altitude difference of 530 metres. More than 50 mountains with a height of over 500 m rise in the town area and characterise the landscape in the south of the town.

There are two villages in each of four valleys:

Bruchhausen and Elleringhausen in the Medebach/Gierskopptal valley at the foot of the Istenberg with its historically significant four porphyry rocks. In the Ruhr valley Assinghausen and Wiemeringhausen, in the Neger valley Brunskappel and Wulmeringhausen. And in the Elpe valley are Gevelinghausen and Elpe with the former miners' settlement of Heinrichsdorf. This district at an altitude of 630 metres is the highest settlement in the town.

The eastern city boundary forms the state border between North Rhine-Westphalia and Hesse over a length of 2.5 kilometres to Willingen/Upland. The watershed between the Rhine and Weser also runs here. Its southern neighbour is the town of Winterberg.

The town of Olsberg is only connected to the town of Schmallenberg by a point near the Elper Steinmarkskopf. This is also where the western border with the municipality of Bestwig begins. In the north, the Antfeld district forms an approximately 4 km long border between the Hochsauerland district and the district of Soest (town of Rüthen).

The economic structure of Olsberg is characterised by trade and industry as well as private and public services. A second important pillar is tourism and healthcare. Tourism plays a special role in our town. The foundation stone was laid in 1894 by Dr Grüne, a student of Pastor Kneipp, with the construction of a sanatorium. In the health sector, the Elisabeth Clinic, a specialised clinic for orthopaedics, rheumatology, accident and reconstructive surgery and internal medicine as well as the German Aslan Institute with the ASLAN Kurpark Clinic are worthy of mention.

Olsberg has lively villages. Proof of this is the "largest citizens' initiative in Germany", namely the competition "Our village should become more beautiful". The name of the competition was correctly added "Our village has a future". Assinghausen won a gold medal at national level in 1989. Elleringhausen won gold in the state competition and silver in the national competition. Bruchhausen was the crowning glory: The village an den Steinen won the gold medal in the European competition for greenery in towns and villages "Entente Florale" in 1998, making it one of the most beautiful villages in Europe.

The town of Olsberg was granted the right to bear a coat of arms with the approval of the district president on 10 March 1978.

Description of the coat of arms:

Squared of yellow and red, above a free-standing black ring with superimposed black squares, each sitting in the centre of the adjoining fields.

The squared fields in yellow and red were taken from the coat of arms of the former municipality of Brunskappel, now Olsberg. Gold and red were the colours of the bailiffs of Grafschaft, who had their seat on the Wildenberg estate in Brunskappel. The free-standing black ring with the four black squares symbolises

• the Germanic refuge on the Istenberg with the four Bruchhauser stones as the most significant historical and scenic feature of the town of Olsberg,
• the powerful merger of the formerly independent communities in the four valleys of the Ruhr, the Neger, the Elpe and the Medebach and the Gierskopp to form the town of Olsberg,
• the black ring is the "O" for Olsberg.

The use of the coat of arms must be authorised by the town of Olsberg.

On 17 July 1986, the Olsberg town council decided to build the town hall on the basis of a financing concept. From the outset, it was a declared aim to create a meeting place with the new building. The state and federal government later provided financial assistance totalling around DM 1.6 million for the rooms for the citizens' meeting centre and the public library.

Construction began on 27 March 1987 with the ground-breaking ceremony by Mayor Josef Niggemann.

On 26 June 1987, the foundation stone was laid for the modern town hall in the heart of the town. The topping-out ceremony took place on 23 October 1987 in the Bigge Schützenhalle.

After almost 2 years of construction, the move from the old Bigge office building to the new town hall took place on 13 and 14 January 1989. On Monday 16 January 1989, the new town hall opened for business.

The unusual service centre was handed over to the citizens with a public festival on 13 and 14 June 1989.

Dipl. Ing. Peter Scheele from Dortmund is responsible for the architectural masterpiece. The architect and his team developed the floor plan of the building with its ring-shaped access and the internal "town courtyard" from the Olsberg town coat of arms. The light-filled construction was very well received by the townspeople. The building cost DM 8.4 million.

In 1999, the 10th anniversary of the town hall was celebrated with a festival "Around the Town Hall".