According to the Framework Act on Forestry, mountainous areas refer to areas (Eup·Myeon) in which the ratio of forest land area is 70% or more, the population density is below the national average, and the ratio of agricultural land is below the national average of rural areas (Eup·Myeon). As of 2014, 466 Eup·Myeon were included in mountainous areas. The purpose of this study is to classify the types of mountainous areas according to location characteristics and to analyze the socio-economic changes of each type of location in mountainous areas. To classify the type of mountainous areas, K-means cluster analysis was conducted according to location characteristics (forest land ratio, agricultural land ratio, average elevation, distance to large cities) for 452 Eup·Myeon, excluding 14 Eup·Myeon in island. Depending on the type of mountainous areas, population density, aging rate, youth ratio, farm household ratio, forestry household ratio, main industry, number of workers, and number of workers by industry were measured in 2010, 2015, and 2020. As a result, mountainous areas were classified into three types (mountain, intermediate, and rural type), with 83 mountain type Eup·Myeon, 169 intermediate type Eup·Myeon, and 200 rural type Eup·Myeon. Mountain type areas have a low population density, proportion of an aging population, and farm household and a high proportion of the young, forestry household, and workers in lodging and restaurants businesses while rural type areas have a high population density, proportion of an aging population, farm household, and workers in manufacturing businesses and a low proportion of the young and forestry household. From 2010 to 2020, population density, youth ratio, farm household ratio, and forestry household ratio decreased and aging ratio and number of workers increased in all types of mountainous area. In order to maintain the diversity of them, it is necessary to establish policies considering the location characteristics and functions according to the type of mountainous areas.