The Shinetsu Main Line is a railway line, consisting of three geographically separated sections, operated by the East Japan Railway Company in Japan. It was originally one continuous line connecting Takasaki and Niigata via Nagano. Since the opening and later extension of the Hokuriku Shinkansen, sections running in parallel have either been discontinued or transferred to third-sector railway companies.

The East Japan Railway Company is a major passenger railway company in Japan, the largest of the seven Japan Railways Group companies. The company name is officially abbreviated as JR-EAST or JR East in English, and as JR Higashi-Nihon in Japanese. The company's headquarters are in Yoyogi, Shibuya, Tokyo, next to Shinjuku Station. It is listed in the Tokyo Stock Exchange, is a constituent of the TOPIX Large70 index, and is one of three Japan Railways Group constituents of the Nikkei 225 index, the others being JR Central and JR West.