Olten is a town in the canton of Solothurn in Switzerland and capital of the district of the same name.

Olten's railway station is within 30 minutes of Zurich, Bern, Basel, and Lucerne by train, and is a rail hub of Switzerland.

Despite the presence of numerous archaeological evidences of early habitation, Olten is first documented in 1201 as Oltun. It became important in the 13th century because of its bridge over the Aar River. This geographical fact has determined much of its history. Mgr.Bruno Bernard Heim was born in Olten.

Olten has an area, as of 2009^[update], of 11.49 square kilometers (4.44 sq mi). Of this area, 1.46 km² (0.56 sq mi) or 12.7% is used for agricultural purposes, while 4.81 km² (1.86 sq mi) or 41.9% is forested. Of the rest of the land, 4.65 km² (1.80 sq mi) or 40.5% is settled (buildings or roads), 0.53 km² (0.20 sq mi) or 4.6% is either rivers or lakes and 0.06 km² (15 acres) or 0.5% is unproductive land.

Of the built up area, industrial buildings made up 6.0% of the total area while housing and buildings made up 15.6% and transportation infrastructure made up 11.6%. Power and water infrastructure as well as other special developed areas made up 4.2% of the area while parks, green belts and sports fields made up 3.1%. Out of the forested land, 40.7% of the total land area is heavily forested and 1.1% is covered with orchards or small clusters of trees. Of the agricultural land, 6.2% is used for growing crops and 5.9% is pastures. All the water in the municipality is flowing water.