A selection of websites for finding running races, especially marathon distance and longer.

Runners World UK (login required) - many UK races.

100 Marathon Club - a comprehensive list of UK, Ireland and rest of the world marathons and ultras.

Multidays - worldwide  multi-day and ultra distance races.

LDWA (Long Distance Walkers Association) - UK "challenge" events open to both runners and walkers.

Sleepmonsters - worldwide adventure races.

Trailscape - series of four trail marathons.

GoBeyond Ultra - excellent UK distance races.

MarathonGuide - international marathon calendar.

Marathon Maniacs - US based marathon calendar.

Extreme Energy - UK based multidays and ultras.

Madeyarun - mostly Uk marathons.