The Ryōmō Line is a Japanese railway line connecting Oyama in Tochigi Prefecture with Maebashi in Gunma Prefecture. 84.4 km (52.4 mi) long, the line is owned and operated by the East Japan Railway Company. The name refers to the fact that Gunma and Tochigi prefectures were once part of an ancient province called Keno (毛野), which was later split into Kōzuke (Gunma) and Shimotsuke (Tochigi). This line connects both halves of the old province.

Oyama is a city located in Tochigi Prefecture, Japan. As of 1 August 2020, the city had an estimated population of 167,647 in 70,928 households, and a population density of 980 persons per km2. The total area of the city is 171.76 square kilometres (66.32 sq mi). In 2006, Oyama became the second most populous city in Tochigi Prefecture, with the capital Utsunomiya retaining the number one spot.