The Keikyu Main Line is a railway line in Japan, operated by the private railway operator Keikyu. The line connects the Tokyo wards of Minato, Shinagawa, Ōta, and the Kanagawa municipalities of Kawasaki, Yokohama and Yokosuka. The Keikyu Main Line began as a short 2 km (1.2 mi) line in 1895. By 1905 it was extended from Shinagawa Station in Tokyo to central Yokohama, becoming a major interurban line between the two cities.

Keikyu Corporation , also known as Keihin Kyūkō (京浜急行) or, more recently, Keikyū (京急), is a private railroad that connects inner Tokyo to Kawasaki, Yokohama, Yokosuka and other points on the Miura Peninsula in Kanagawa Prefecture. It also provides rail access to Haneda Airport in Tokyo. Keihin (京浜) means the Tokyo (東京) - Yokohama (横浜) area. The company's railroad origins date back to 1898, but the current company dates to 1948. The railway pioneered Kantō region's first electric train and the nation's third, after Hanshin Electric Railway and Nagoya Electric Railway (Meitetsu) with the opening of a short 2 km (1.2 mi) long section of what later became the Daishi Line in January 1899.