Sweden's counties are primarily administrative units, whereas the provinces of Sweden usually fit cultural and historical boundaries. Örebro County consists of the province of Närke, the western half of Västmanland and minor parts of eastern Värmland and northeastern Västergötland. Örebro County is named after its capital city, Örebro, which in 2010 was the sixth largest city of Sweden. Official 2010 numbers sourced in the localities section indicate that 38 % of the county population is living in the city of Örebro alone. Örebro itself contains just as many inhabitants as the 23 other largest localities put together, and has grown significantly ever since the official statistics began in the late 1960s.
The southern Närke plain, the forested north and the highland to the west makes for a varying landscape. Örebro County is located between the four major lakes of Sweden and has coastlines on two of them. Capital Örebro is alongside Hjälmaren, located slightly inland along Svartån. The southern area of the county has a transitional climate between oceanic and continental, with warm summers and cold, variable winters. Örebro has a July high of around 23 °C (73 °F) and winter highs around 0 °C (32 °F) with frosts being frequent from November to April. The proximity to the major lakes moderates winter temperatures somewhat, undermining the continental effects of its inland position. The northern areas of the county are slightly cooler year-round. The summer temperatures on the Närke Plain are some of the warmest in all of Scandinavia and by extension Northern Europe.