Since the recent financial crisis in universities has caused the decrease of academic library budget, the resource sharing has been considered by utilizing inter-library loan (ILL) data for solving the financial deficit. This study aims to identify the collection profiles of western monographs’ ILL data among 4-year academic libraries. In order to achieve the purpose of this study, this study analyzes ILL data from 2011 to 2017 using the bibliographic data and ILL transactions of the KERIS union catalog. The findings of the study show that the western monographs was significantly provided by large-scale academic libraries in 2011, however, the extent of major regions expanded, and the number of influential institutions rose in 2016. Second, in 2012, the influence in the ILL network increased in the quantity of western monographs holdings and the proportion of common collections. On the other hand, in 2016, it was also shown that the influence in terms of provision in the ILL network increased in the proportion of unique collections. Lastly, the ILL participating academic libraries were classified into six clusters by a hierarchical clustering analysis of holdings and ILL indexes.