This corpus-based study examined the usage, mastery and developmental pattern (Norwati, 2004) of English prepositions of place, "in" and "on" across three different academic levels namely Form 4, Form 5 and College students. The Malaysian Corpus of Students Argumentative Writing (MCSAW) was used as the source of data in analyzing the use of prepositions of place, "in" and "on" in the students' argumentative essays. In achieving this, the concordance output was utilized to determine the frequency and types of errors made by students. This paper also presents other common errors in relation to the usage of these two prepositions. The findings showed that in terms of mastery levels and developmental pattern, there was no steady progress from Form 4 to Form 5. Yet, the College students managed to show a positive development in the use of prepositions of place, "in" and "on." The findings also revealed that students are confused between "in" and "on" as well as using them with or without articles correctly. The findings of this study can benefit English teachers in teaching prepositions of place and the use of MCSAW can be fully utilized by teachers for further future researches.