Toyohashi is a city in Aichi Prefecture, Japan. As of 1 December 2019, the city had an estimated population of 377,453 in 160,516 households a…Toyohashi is a city in Aichi Prefecture, Japan. As of 1 December 2019, the city had an estimated population of 377,453 in 160,516 households and a population density of 1,400 persons per km². The total area of the city was 261.86 square kilometres. By area, Toyohashi was Aichi Prefecture's second-largest city until March 31, 2005, when it was surpassed by the city of Toyota, which had merged with six peripheral municipalities.