Situated in the eastern part of Transylvania, along one of the main routes of the region, Csíkszereda is the heart of Harghita County. It lies in a central location within the Szeklerland, 100 km north of Braşov, 150 km east of Târgu Mureş and 242 km east of Cluj Napoca, on the left bank of the river Olt.

Csíkszereda can be approached on public roads from several directions. From the west – from the direction of Odorheiu Secuiesc – it can be reached by taking National Road 13A. From north to south the town is crossed by European Route E 578 overlapping with National Road 12. If travelling By air, the closest airports are the Bacău International Airport (124 km) and the Târgu Mureş International Airport (157 km). As far as railway travel is concerned, Csíkszereda lies on the main rail line no. 400, which links the town with other regions of the country.

Csíkszereda is the geographic, economic and cultural centre of the Ciuc Basin, the population of which is about 150,000. According to the 2011 census, the town is inhabited by 37,980 people, comprising nearly 25% of the Ciuc Basin's total population. About 80% of the town's inhabitants are ethnic Hungarians, and more than 70% belong to the 15 to 59 age group.

The region is particularly rich in mineral springs, a potential that has favoured the opening of a number of lidos and mineral water bottling plants. The agriculture is increasingly based on animal husbandry, a tendency strengthened by the high proportion of hayfields (46%), fodder cultivation on arable lands, as well as by the growing number of cattle farms.

Harghita Băi is a climatic resort belonging to Csíkszereda, known for its mofette and mineral springs. It is situated 21 km west of Csíkszereda at an altitude of 1350 m above sea level. The gas emanations from the mofette are recommended for the treatment of diseases such as chronic arthritis, high blood pressure, stenosis, venous vascular lesions, sclerodermatitis, discopathia, radiculopathy and spondylosis. In summer Harghita Băi is a popular place for hiking, while in winter it is the most frequented ski-resort in the region, with an adventure park, several well equipped ski slopes, hire shops and various possibilities for accommodation.

The Şumuleu Ciuc pilgrimage site is one of the most important sacral places in Transylvania, with developed infrastructure and dramatic scenery. Besides the Pentecost Pilgrimage, the Day of a Thousand Szekler Maids and other programmes are also organised here.