The western part (Otsu and Takashima Cities) is a key area which connects 'Kinai' and Wakasa Bay/Hokuriku region in the shortest way and Nishiomiji Road and Saba-kaido Road (the highway used to transport fish such as 'saba' [mackerel] to Japan's ancient capital, Kyoto) went through the part in the Edo period.
西部（大津市と高島市）は畿内と若狭湾・北陸とを短絡する要地であり、江戸時代には西近江路・鯖街道が通っていた。