BOISE -- The annual Ironman event will cause some road closures, traffic delays, and detours on Saturday, the Ada County Highway District said.

More than 1,200 athletes are expected to participate in the grueling triathlon, in which competitors swim, bike, and run through a challenging course.

The events will take place in and around Boise starting mid-morning on Saturday and will continue throughout the day.

The race begins at Lucky Peak's Barclay Bay for the swim portion of the event, followed by biking 56 miles through east and southeast Boise. The last leg of the race is a 13.1 mile run, mostly along the Greenbelt to the finish line at Julia Davis Park.

To see maps of the course, CLICK HERE.

ACHD says there will be multiple closures, traffic delays, and detours on local and state roads that will serve as the biking and running courses.

However, officials say some changes made this year mean that no roads will be closed for multiple days and Front and Myrtle streets in downtown Boise will not be impacted.

Police and event volunteers will be on hand along race routes to direct traffic and, in some areas, to assist residents with accessing or leaving their homes.

Here's a look at the various traffic impacts, according to ACHD:


  • Capitol Boulevard from Protest Avenue to Myrtle Street - Closed from 11 a.m. to 8 p.m.
  • Capitol Boulevard from Protest Avenue to River Street - Closed from 11 a.m. to 6:30 p.m.
  • Capitol Boulevard from University Drive to River Street - Closed from 11 a.m. to 12 a.m.


  • I-84 Freeway Interchange at Eisenman Road - Closed 12:40 p.m. to 5 p.m.
  • S. Eisenman Road from I-84 to the Factory Outlet - Closed 12:50 p.m. to 4:45 p.m.
  • Pleasant Valley Road from Gowen Road to Ten Mile Creek Road - Closed 1 p.m. to 4:45 p.m.
  • Ten Mile Creek Road from Pleasant Valley Road to S. Cole Road - Closed 1:20 p.m. to 4:30 p.m.
  • Federal Way and S. Capitol Boulevard from Protest Road to University Drive - Closed from 1:30 p.m. to 6:30 p.m.


  • US Highway 21 from Lucky Peak Dam to Warm Springs Avenue - Delays between 12:20 p.m. and 2:20 p.m.
  • US Highway 21 from Warm Springs Avenue to Technology Way -Detour through Grand Forest Drive from 12:30 p.m. to 5:30 p.m.
  • US Highway 21 from Technology Way to the Diversion Dam - Lane impacts; expect delays between 12:30 p.m. and 5:30 p.m.
  • Bown Way from Warm Springs Avenue to Boise Avenue - Expect delays between 2:10 p.m. and 5:45 p.m.
  • Boise Avenue from Bown Way to Holcomb Road - Expect delays between 2:15 p.m. and 5:45 p.m.


  • Gowen Road from S. Eisenman Road to Pleasant Valley Road - Westbound traffic only between 12:50 p.m. and 4:45 p.m.
  • Warm Springs Avenue from US Highway 21 to Bown Way - Northbound traffic only between 2 p.m. and 5:40 p.m.
  • Holcomb Road/Bergeson Street from Boise Avenue to Federal Way - Eastbound-only traffic allowed between 2:15 p.m. and 6 p.m.
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