Runners who laced up for the 2017 Boston Marathon sprinted by 19.7M SF of commercial space along the 26.2 miles from Hopkinton, Mass., to the finish line in Copley Square. Rents more than triple along a course that starts in a largely residential area and ends amid some of the region's most desirable real estate in Boston's Back Bay, JLL reports. With 500,000 spectators expected to attend, the modern world's oldest marathon is New England's most-attended athletic event.

The Starting Line

Mile Mark: 0

Towns Crossed: Hopkinton, Ashland, Framingham, Natick

Development: The office vacancy rate is 18% at the starting line in Hopkinton and rents average in the mid-teens to low $20s in these early miles, according to NAI Hunneman director of research Liz Berthelette. Framingham, the largest suburban town along the marathon, has 3.8M SF of offices. While the course itself does not have too much CRE on this early stretch, runners have a soft spot thinking of the soft serve ice cream being made at the Dairy Queen they pass just beyond the four-mile mark in Ashland.

Route 128/Mass Pike

Mile Mark: 12.4

Towns Crossed: Wellesley, Newton

Development: “The only downside of being along the marathon route is if you want to get to your office on Marathon Monday," Auburndale Realty president and Society of Industrial and Office Realtors member Robert Nahigian said. "But it’s a local holiday, and that’s what back doors are for.”

His firm is near the Newton Firehouse (between the 16- and 17-mile mark) and specializes in suburban Boston. Along with the women of Wellesley College’s “Scream Tunnel,” runners will notice several older buildings have been converted to medical offices like Shields MRI's space on Washington Street in Wellesley Hills. Proximity to hospitals like MetroWest Medical Center and more doctors wishing to be closer to suburban patients is sparking the change, he said. Sadly, they cannot take away the pain induced by Heartbreak Hill a few miles ahead.

Heartbreak Hill

Mile Mark: 20.5

Towns Crossed: Chestnut Hill, Boston-Brighton, Brookline

Development: While the incline itself is gradual, Heartbreak Hill’s placement at the 20.5-mile mark is brutal. By the time runners cross into Boston proper on the other side of the hill’s peak, they will face Boston College’s new 240K SF Thomas More Apartments residence hall and a slew of cheering students. The course is mainly downhill from the 22-mile mark into Brookline and offers a view of the 30-story Pierce Boston under construction in the Fenway neighborhood.

Kenmore Square

Mile Mark: 25.2

Towns Crossed: Boston-Fenway/Kenmore

Development: This is when marathoners begin to taste the finish. Kenmore Square’s iconic Citgo sign awaits along with the rest of Related Beal’s nine-building portfolio (purchased in 2016) in the neighborhood. Red Sox fans from the traditional Patriots Day game earlier in the day at Fenway Park usually cheer on the runners in front of the recently expanded Hotel Commonwealth.

"Right On Hereford, Left On Boylston"

Mile Mark: 26

Towns Crossed: Boston-Back Bay

Development: After taking a right on Hereford and left on Boylston, the finish line is sprinting distance away. Runners this year will notice a significant change from prior Boston Marathons. Boston Properties has opened the 17-story, $275M 888 Boylston above its Prudential Center mall. Mario Batali opened a 45K SF Eataly in the new building’s bottom three floors.

The Finish Line

Mile Mark: 26.2

Towns Crossed: Boston-Back Bay

Development: Runners will sprint by the $78M Boston Public Library Johnson building renovation (opened last summer) as they cross over the finish line. Athletes will grab a thermal blanket and hit one of Boylston Street’s many restaurants, which are preparing with extra staff and security to accommodate the swarm of marathoners.

“This is the day we try to break records,” Travis Mitchell, general manager of Joe’s American Bar & Grill on Newbury Street, said.

Located just past the finish line, Joe’s is a spectator and runner favorite and has 176 cases of beer, 45 kegs and 122 cases of liquor ready for Marathon Monday. The heightened volume of people in the area has led the restaurant to hire extra security on easily its busiest day of the year. Mitchell and executive chef Dan Billo said Marathon Monday, which is preceded by Easter Sunday and falls during spring break this year, is a lot of work but also a lot of payoff — if you prepare.

“Disaster is lurking around the corner if you miss anything,” Billo said.