Rita Jeptoo of Kenya successfully defended the Boston Marathon title she said she could not enjoy a year ago after the fatal bombings.
Jeptoo finished Monday's race in a course-record 2 hours, 18 minutes, 57 seconds. She becomes the seventh three-time Boston Marathon champion.
Jeptoo broke away from a group of five runners at the 23-mile mark. Buzunesh Deba finished second with an unofficial time of 2:19:59.
American Shalane Flanagan finished fifth after leading for more than half the race.
Lanni Marchant of London, Ont., was the top Canadian in 14th.
Meanwhile, American Meb Keflezighi won the Men's Marathon, a year after a bombing at the finish line left three dead and more than 260 people injured.
Keflezighi is a former New York City Marathon champion and Olympic medallist.
He ran the 26.2 miles from Hopkinton to the finish on Boylston Street in Boston's Back Bay on Monday in 2 hours, 8 minutes, 37 seconds.
Keflezighi held off Wilson Chebet of Kenya who finished 11 seconds behind. The 38-year-old from San Diego looked over his shoulder several times over the final mile. After realizing he wouldn't be caught, he raised his sunglasses, began pumping his right fist and made the sign of the cross.
No U.S. runner had won the race since Lisa Larsen-Weidenbach took the women's title in 1985; the last American man to win was Greg Meyer in 1983.