Yes. The men's marathon is one of the few events that has been held in every Modern Olympics. The women's marathon began in 1984.

http://en.wikipedia.org/wiki/Athletics_a...

Yes, there is an olympic marathon in the summer olympics.

the first men's marathon was introduced at the 1896 modern olympics (athens)

The women's marathon was introduced at the 1984 Summer Olympics (Los Angeles, USA)

yes

It sure is