The 400-mile course starts at Sheep Mountain Lodge, follows the same route as the 200-mile course through Glennallen and into Valdez. The course then turns around at Captain Joe's Gas Station, 139 Pioneer Drive, in Valdez and returns by the same route to Sheep Mountain Lodge. No drafting is allowed for soloists or relay riders. Fireweed 400 riders may use any aid stations open during Saturday's racing events if those stations are open when the riders pass them. Because the Fireweed 400's time schedule differs so greatly from the times scheduled in other events, Fireweed 400 riders should not count on these aid stations being open, and must plan to be self-supported.




| Event | Name | Time | Year |
|---|---|---|---|
| 400 F TT | Janice Tower | 25:17:18 | 2003 |
| 400 M TT | Jeff Oatley | 19:56:32 | 2006 |
| 400/2 M Person | Ben Larson and Kenneth Philbrick | 18:23:54 | 2005 |
| 400/2 Person F | |||
| 400/2 Person Mixed | Annie and Dennis Ronsee | 21:03:49 | 2007 |
| 400/4 Person M | Tim Lamb, Jens Beck, Andy Duenow, and Kevein Donley | 16:56:30 | 2003 |
| 400/4 Person Mixed | Greg Russell, John Thornley, Mary Holozubic, Jennifer Esteri | 19:35:16 | 2004 |
| 400/ 2 Person Mixed Tandem | Andrew Pohl and Judith Abrahams | 22:28:49 | 2005 |