The building at the hospital's downtown campus will be bounded by Cambridge, Blossom, Parkman and North Grove streets and will partially span over a portion of North Anderson Street, according to the hospital's filing with the BPDA.

The existing Parkman Street Garage, the Professional Office Building and several other older structures will be demolished in connection with the new development.

The hospital also plans to build a new Campus Services Building at 30 Blossom St. that will replace an existing utilities building at the site. The 81,000-square-foot, seven-story building will feature approximately 29,500 square feet of administrative support space and will also include two stories below grade.

According to several published reports, hospital officials are hopeful to begin construction on the project in 2020 and complete the expansion by 2026.

Boemer told the BPDA in the filing that the expansion project was the result of a comprehensive planning process that was focused on modernizing the MGH campus. Massachusetts General Hospital, which was founded in 1811, is the third oldest general hospital in the United States.

She explained, “In recent years the need for the hospital to rebuild and renovate its main campus has become increasingly pressing as demands for services have increased and facilities required to deliver the highest standard of care have evolved.”

Boemer continued, “Currently, MGH delivers advanced care in several facilities that are outdated and inefficient.” She added that the planning process and the proposed expansion “sought to identify ways to integrate rapidly expanding medical technologies, mitigate severe Emergency Department overcrowding, address a need for single patient rooms; and respond to significant sustainability and resiliency challenges.”