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. In 2006, Oyama became the second most populous city in Tochigi Prefecture, with the capital Utsunomiya retaining the number one spot.