The Chiba New Town Railway 9100 series (千葉ニュータウン鉄道9100形) is a commuter electric multiple unit (EMU) train type owned by the third-sector railway company Chiba New Town Railway and operated by the Hokuso Railway on the Hokuso Line in Japan since 1994.

[1] The trains are nicknamed "C-Flyer", with the "C" standing for Chiba.

[2] The 1st-batch sets, 9101 and 9111, originally had public phones located in cars 3 and 6, but these were removed in 1997.

[1] The first two sets, 9101 and 9111, were built by Nippon Sharyo in Toyokawa, Aichi, and delivered in 1994, ahead of the extension of the Hokuso Line from Chiba New Town Chūō to Inzai-Makinohara in 1995.

[1] A third, 2nd-batch set, 9121, was delivered in 2000, coinciding with the extension of the line from Inzai-Makinohara to Inba-Nihon-Idai.