The IMT Des Moines Marathon is a perfect size event with 9,000 runners. Large enough that you have plenty of runners to run with but small enough that you feel like you're part of the IMT Des Moines Marathon family," said Bart Yasso, Runner's World Chief Running Officer. Oct 20, 2019 · IMT Des Moines Marathon 2019 - Emilene Leone Sunday, October 20, 2019 in Des Moines, IA Hello! Trees Forever is a fantastic organization, one that really educated me about the importance of planting native trees and plants. They are doing good work and I want to run the half marathon is support of this organization.