横雲橋, Bridge structure in Agano, Japan

Yokoumon Bridge is a road bridge in Agano that crosses a river with a straightforward, functional design. The structure allows both pedestrians and vehicles to move between the two banks, serving as a practical transportation link for the area.

A wooden bridge 311 m long and 5.4 m wide opened here in October 1875; the prefectural governor Kusumoto Masataka named it Yokoumon for its span that looked like clouds trailing over the great river. The fifth and current bridge opened on 8 May 1963 as part of improvements to National Route 49.

The name Yokoumon comes from a remark by Niigata governor Kusumoto Masataka, who in 1875 described the long wooden bridge as a great river with clouds trailing across it. The current 1963 span carries Niigata Prefectural Route 586 between Fukahori in Agano and Yokogoshi-chuo in Konan Ward, Niigata.

The bridge carries two lanes of the Niigata Prefectural Route 586 Suibara-Kameda line, with a separate pedestrian bridge attached on the downstream side. Vehicles over 20 tonnes need a special permit in advance; without one they must detour via the Shin-Yokoumon Bridge on National Route 49 upstream. The east end is in Fukabori, Agano; the west end in Yokogoshi-chuo, Konan Ward, Niigata.

The name was chosen in 1875 by Niigata governor Kusumoto Masataka, who described the first wooden bridge as stretching over the great river like trailing clouds. The current bridge, the fifth, opened on 8 May 1963 as part of improvements to National Route 49.