The Uchibō Line (内房線, Uchibō-sen^?) is a railway line operated by the East Japan Railway Company (JR East) along Tokyo Bay, on the western (i.e., inner) shore of the Bōsō Peninsula. It runs from Soga Station in the city of Chiba to Awa-Kamogawa Station in the city of Kamogawa, passing through the municipalities of Chiba, Ichihara, Sodegaura, Kisarazu, Kimitsu, Futtsu, Kyonan, Tateyama, and Minamibōsō. The line is connected on both ends to the Sotobō Line. The name of the Uchibō Line in the Japanese language is formed from two kanji characters. The first, 内, means "inner" and the second, 房 is the first character of the Bōsō. The name of the line thus refers to its location along the inner part of the Bōsō Peninsula in relation to the Tokyo Metropolitan Area, as opposed to the Sotobō Line, "outer Bōsō" which is on the opposite side of the peninsula.

The Uchibō Line operates local service with trains generally originating and terminating at Chiba Station. Trains headed directly for Tokyo Station merge with the Sotobō Line between Soga and Chiba Stations, and with the Sōbu Main Line between Chiba and Tokyo, while express and commuter trains merge with the Keiyō Line from Soga station.