On maps, diagrams and signboards, the line is colored green, and its stations are given numbers following the letter "K".

It serves seven of Kyoto's eleven wards: Sakyō-ku, Kita-ku, Kamigyō-ku, Nakagyō-ku, Shimogyō-ku, Minami-ku, and Fushimi-ku.

Between Kitaōji and Jūjō, trains run beneath the north–south Karasuma Street, hence the name.

This line covers a total distance of 13.7 km (8.5 mi) in 26 minutes and the average daily ridership in 2009 was 411,881 passengers.

[1] Through services from Kitaōji to Shin-Tanabe on the Kyoto Line started on August 28, 1988.