The race, which brings in over $200 million to the city's economy, has never been cancelled in its 124-year history.
Earlier this week, Boston cancelled the annual St. Patrick's Day Parade in South Boston.
Several colleges have moved to online-only classes, and schools around the state have closed.
A runner at the finish line told WBZ NewsRadio that she is disappointed the race will likely be moved, but she understands taking the measure. "I feel like it's a little early.... but it's better to take precautions than to regret it later."
WBZ NewsRadio's James Rojas (@JamesRojasWBZ) reports: