Code or Boyong River divides the city of Yogyakarta, where the water flows directly from Mount Merapi. During the eruption of Mount Merapi, Code Rives was one of the rivers which water flow was susceptible to cold lava floods that carried pyroclastic (sedimentary) material which impacted on the infrastructure of the river and its borders in the form of building damage and also life-threatening to those around the river border areas. The method used in this study was the quantitative data presentation by a survey of the research location. This research discussed the river boundaries processed using ArcGIS 10.2.1 and adapted to government regulation regarding rivers. The results of this study obtained land-use area within the border with 5-meter width border has 15,028 ha land use, and 50-meter width of the border has 397,87 ha of land-use. Estimation of the population in the river border was also obtained, with 5 meters width of the border has 1650 people, and 50 meters width of the border has 2401 people.