Lydians and the Kingdom of Pergamum have consequently ruled the region, that is home to some of the more important historical sites of the region from Bergama to Allinoi and Sardes. Soma Municipality has existed since 1891 and was established in Ottoman times.
The present geographical area of the district is about 826 square km and total population approxiamately 100,000, according to the 2008 census. Urban population is concentrated in the town of Soma which has a population of 73,000, the rest is rural . Urban migration rates are similar to most of the Aegean region towns at around 5% and is driven by economic dynamics, particularly poor returns in agriculture.
The region is mountainous and tillable land rather limited, although Bakırçay river and basin in the west, provide one of the larger agriculturally usable areas in the northern Aegean. Close to half the district is covered by forest and most agriculture, around 20% of the land is non-irrigated agriculture.
The climate of Soma is in the category of semi-humid Meditteranean climate. Winters are cold and mostly rainy, whereas summers are dry. July is the hottest month and the average temperature of Soma is 23-24°C. In winter, Soma is affected by cold air streams coming from Balkans and the average temperature is low. January is the coldest month with an average temperature of 3-5°C with snowfall.
At the center of economic activity in Soma is the extraction of coal. Coal in this area was discovered in 1913 and Soma lignite provide up to 22% of total Turkish extraction of coal. The estimated reserves (2008) are around 600 milyon tons. The second largest economic entity in the district is the thermal power plant that uses Soma lignite, SEAŞ. SEAŞ, one of the first large central power plants in Turkey was established in 1954 and today provides approximately 4% of the country's electricity.