Chester County Hospital, part of the University of Pennsylvania Health System, is scheduled to start a $90 million, 276,000-square-foot expansion this spring, the largest in its history, Penn said.

The expansion will include 14 modern operating rooms, 10 emergency department rooms, four labs for catheterization and other procedures, and up to 96 inpatient rooms, pending approvals. The expansion is expected to take several years to complete and will give the West Chester hospital a new front entrance, Penn said.

When Penn acquired Chester County Hospital and Health System in 2013, it agreed to spend $130 million on capital improvements and the expansion of services in  the first five years of ownership.

Just before the deal with Penn, Chester County Hospital added a $45 million patient tower, bringing the complex to 535,520 square feet. The hospital has 289 licensed beds.