Reps. Joe KennedyJoseph (Joe) Patrick KennedyPETA rips Tomi Lahren for saying she kicks her dog A Sanders-Warren ticket could win big in 2020 Overnight Health Care: Trump officials block GOP governor from skirting ObamaCare rules | Abstinence-only education makes a comeback | Mississippi passes nation's most restrictive abortion law MORE (D-Mass.) and Kirsten Sinema (D-Ariz.) are running the Boston Marathon that kicks off Monday morning.

“Boston is like the Holy Grail of running events,” Sinema told ABC News. “I never thought I would ever find my toe at the starting line at Boston.”

Their House colleague, Rep. Scott Peters (D-Calif.), wished them luck on Twitter Sunday evening.

Sinema, 37, has already completed eight marathons, and is running in Boston in honor of Martin Richard, the eight-year-old boy killed in last year’s bombings on April 15.

The congresswoman told ABC she has already raised $20,000 for the charity in Richard’s name, Team MR8. His parents chose Sinema and a friend to compete for their son.

The race will be the first marathon for Kennedy, 33, who is running with his wife. He’s running for One Fund, a group established to help the victims and survivors of last year’s bombings.

Security in Boston remained tight Monday as the second-largest field in race history gets ready to begin the 26.2-mile marathon.

More than 35,600 people are registered to run the race.