Which marathon did Kathrine Switzer enter officially in 1967 using the race number 261?

Kathrine Switzer officially entered the 1967 Boston Marathon using race number 261.

Switzer registered as “K. V. Switzer,” because the entry form did not explicitly state that women were barred. She received bib number 261 and started the race with the Syracuse Harriers. Race director Jock Semple attempted to remove her from the course, but fellow runners and officials intervened.

Switzer completed the marathon in roughly 4 hours 20 minutes. Her entry became an internationally recognized moment in the campaign for women’s equal access to distance running, although Bobbi Gibb had run the Boston course unofficially the previous year.

The Boston Athletic Association formally allowed women to enter from 1972. Switzer later founded the Avon International Running Circuit, which helped expand competitive opportunities for women worldwide.