Indian Mountain School is an independent coeducational boarding and day school for children grades pre-K through 9, located on two campuses in Lakeville, Connecticut, United States. The school consists of Lower and Upper campus, with Lower Campus being for children in primary school (pre-k to fourth), while the Upper Campus is home to students grades 5 through 9. However, boarding is only available for students in grades six to nine.Indian Mountain School is often abbreviated as IMS.