A guide to the 2017 Boston Marathon

Briefly: This will be the 121st running of the Boston Marathon. Last year’s champions, Atsede Baysa and Lemi Berhanu Hayle, will be back in Boston to defend their titles. Other past champions in this year’s field include Caroline Rotich of Kenya, Buzunesh Deba of Ethiopia, Meb Keflezighi of the United States, and Wesley Korir of Kenya. The field also includes 16 Olympians and 14 top US runners will also compete in this year’s race. Read more about the elite field here.

8:50: Mobility impaired

9:17: Men’s push rim wheelchair

9:19: Women’s push rim wheelchair

9:22: Handcycles

9:32: Elite women

10:00: Elite men and Wave 1

10:25: Wave 2

10:50: Wave 3

11:15: Wave 4

The route follows Route 135 from Main St. in Hopkinton and goes through Ashland, Framingham, Natick, and into Wellesley. In Wellesley, it continues on Route 16 into Newton, where it turns right onto Commonwealth Ave. (Route 30,) following Comm Ave. through Newton Hills and bearing right at the reservoir onto Chestnut Hill Ave. The route then turns left on Beacon St. continuing into Kenmore Square before rejoining Comm Ave. into the city. The finale sees the route turn right onto Hereford St. and left onto Boylston St. before finishing near the Hancock Tower in Copley Square. See a map of the course here. Track the progress of the marathon here.

A group of elite runners in the 2017 Boston Marathon will participate in a shoe drive in conjunction with One Boston Day.

About 30 runners in the John Hancock elite runner program will donate shoes on April 14 as part of the effort organized by St. Francis House to collect used shoes for those in need. Collection boxes will be placed around the city. The elites will make their donation at the Fairmount Copley Hotel at 9:30 a.m.

Collection locations will be set up April 10 and remain in place through April 14 at the following locations:

■ Boston Marriott Copley Place Hotel (110 Huntington Ave)

■ Cheers Boston (84 Beacon Street)

■ Whole Foods Charles River (181 Cambridge Street)

■ Fairmont Copley Hotel (138 St. James Avenue)

■ City Hall Plaza entrance (near the security check-in)

B.A.A 5K: The 5K will be held Saturday, April 15. Start time is 9:30 a.m. About 10,000 athletes will participate in the event around the Boston Common. This will be the eighth year the race has been held. Registration is closed. Here is the course map.

The Invitational Mile: It will be held Saturday, April 15. The races feature high school athletes from from the eight Boston Marathon towns. There will also be a race featuring professional milers. Here is the course map and the race schedule:

■ Noon: Girls’ middle school 1,000 meters

■ 12:10 p.m.: Boys’ middle school 1,000 meters

■ 12:25 p.m.: Girls’ scholastic mile

■ 12:35 p.m.: Boys’ scholastic mile

■ 12:50 p.m.: Men’s invitational mile

■ 1:00 p.m.: Women’s invitational mile

Sports & Fitness Expo: More than 200 athletic brands, companies, and other exhibitors will fill the John B. Hynes Convention Center for three days to display, promote, discuss, and sell their products. It starts Friday, April 14, and ends Sunday, April 16. Here are the hours each day:

■ Friday, April 14, 10 a.m.-6 p.m.

■ Saturday, April 15, 9 a.m.-6 p.m.

■ Sunday, April 16, 9 a.m.-6 p.m.

Misc.: Runners can begin picking up their official race numbers on Friday, April 14 at the John B. Hynes Convention Center. Pick-up hours each day:

■ Friday, April 14, 10 a.m.-6 p.m.

■ Saturday, April 15, 9 a.m.-6 p.m.

■ Sunday, April 16, 9 a.m.-6 p.m.