Defending champions Ben True of North Yarmouth and Mary Keitany of Kenya will be back to defend their titles in the 20th TD Beach to Beacon 10K on Aug. 5 in Cape Elizabeth.

The elite fields, announced Thursday by race organizers, include three other former racewinners and a two-time Olympic gold medalist.

Last year, True became the first American to win Beach to Beacon, and Keitany broke the women’s course record with a time of 30 minutes, 45 seconds.

True’s likely challengers this year include the 2015 winner, Stephen Kosgei Kibet of Kenya, and another Kenyan, Stephen Sambu, who won the New York City Half Marathon in March. Sambu finished second behind True at the B.A.A. 5K in April when True broke his own American 5K road race record.

Will Geoghegan, a former Brunswick High star, also is returning for the first time since his eighth-place finish in 2015.

The women’s field includes three former winners – Keitany, Wude Ayalew of Ethiopia (2015) and Joyce Chepkirui of Kenya (2013) – as well as Meseret Defar of Ethiopia, the 2004 and 2012 Olympic champion at 5,000 meters.

In addition to her victory last year, Keitany won the New York City Marathon for the third straight year. This April, she won the London Marathon for the third time in 2:17:01 – the fastest women’s marathon ever without male pacesetters.

The top American women in this year’s Beach to Beacon field are Shalane Flanagan, an Olympic silver medalist who finished second in 2014, and Jordan Hasay, who placed fourth in 2014.

For the second straight year, the elite women will get a 12-minute head start before the rest of the 6,500-plus runners begin their journey to Fort Williams Park.