Independent / Non-series

These are events that stand alone: city marathons, national championships, one-off ultras, races that predate the series era and never joined one. 276 are marathons and 186 are half marathons, so the centre of gravity is road running, but the tail runs long. There are 38 races at 104 km and 30 at 160 km in here.

The United States accounts for 231, which reflects where race calendars are best published rather than where the racing is. Japan, India and Spain follow, and the spread reaches 91 countries.

Being independent is not a quality judgment. Some of the oldest and hardest races in the world have no series behind them, and a race that answers to nobody can keep a course, a cut-off or an entry system that a franchise would have standardised away years ago.

Because there is no shared format, read each race on its own terms. Difficulty across this page runs the full range, from 2 out of 5 to 4, with 407 of the 540 sitting at 3.