The ING Georgia Marathon and Half-Marathon passed a milestone this week and is two-thirds of the way toward a sellout.

Organizers of the second-year race announced Wednesday that more than 10,000 participants have signed up.

The field is limited to 15,000 runners, walkers and wheelchair racers. Among the runners expected for the March 30 race are defending marathon champions Joseph Chirlee and Valentina Levushkina.

The race sold out the same number of spots last year in its inaugural running from downtown Atlanta to Decatur and back. According to Running USA, last year's race was the second-largest inaugural combo running event of all time.

"It's a great course," said race director Victoria Seahorn. "Every winner last year mentioned the course and the spectators. It's that winning combination that attracts the elite and inspires every runner, walker and wheeler."

Based on registrations through Monday, more than 3,000 runners have signed up for the 26.2-mile marathon, and nearly 80 percent of all runners are from Georgia, even though all 50 states and 19 countries are represented.

Course marshals needed

Becky Rentz, the race's director of volunteer programs, said despite around 1,600 volunteers having registered, there's still a big need for course marshals — "a great way to get a front-row seat," she said. Organizers are looking for 2,500 volunteers for the three days of events surrounding the race.

"In addition, we are looking for 40-50 runners who can double-duty at the start area as corral monitors, and help organize our wave starts before they take begin their own run," Rentz said.