Päijät-Häme is a region in Southern Finland south of the lake Päijänne. It borders the regions of Uusimaa, Kanta-Häme, Pirkanmaa, Central Finland, South Savo and Kymenlaakso. The biggest city in the region is Lahti.

Lahti is a city in Finland and the regional capital of Päijät-Häme. It is located in the Finnish Lakeland. The population of Lahti is approximately 121,000, while the sub-region has a population of approximately 204,000. It is the 9th most populous municipality in Finland, and the sixth most populous urban area in the country.