The purpose of this study is to analyze the impact on land-use and population change in a rural area close to the construction of a new expressway through location modeling with spatial interaction analysis. Chungbu Expressway, constructed in 1987, going through the southern area of Kyunggi Province from Seoul, Republic of Korea, was selected as a case expressway, and two cities and 18 county subdivisions in its surrounding area, as a case study area. To analyze the change in characteristics before and after the construction, land-use maps of 1986 and 1996 were collected, including census data for the years in cities’ and counties’ yearbooks. Remote sensing technology was applied to classify the land-use maps with six types of land use. A geographic information system was also used for spatial analysis, such as land-use and accessibility changes. A 5-km buffer zone from the tollgate of the expressway showed about two times the increase of urbanized, built-up areas than a 5-km buffer zone from the expressway. Accessibility from Seoul and cities was improved in most areas, which is accessing Seoul through the existing Youngdong Expressway. Ten rural areas showed increased population with an average accessibility of 52min to Seoul and 19min to cities, while eight areas showed decreased population with an average of 73min to Seoul and 35min to cities. This shows the threshold time, which is the time distance from Seoul and middle cities, for population increase or decrease (66 and 33min, respectively) by optimizing the spatial interaction model developed empirically in this study. Urbanized areas were increased in most areas, even in population decrease areas. This indicates that there are thinning rural areas and increasing urbanized areas while population decreases at the same time.