Resources and opinions on topics ranging from training and racing tips to equipment recommendations.

A 200-kilometer event located in Manaus, Amazonia, Brazil. Provides registration details, an overview of the event, rules, and itinerary.

Official site for this annual historic ultra-distance race of 246 km, starting in Athens and finishing in Sparta, Greece. Provides news, history of the event, race calendar, map route, and history.

Provides general information on the sport, especially focusing on northern California. Includes information and statistics for the top races in the USA, as well as personal achievements, and goals.

Sponsor of multi-day races, including the world`s longest certified race of 3,100 miles, triathlons, and many ultra events in more than 30 nations. Includes news, photos, race information, library and links.

135-mile race from Badwater in Death Valley (elev. 282 feet below sea level) to Whitney Portals on Mt. Whitney (elev. 8360 feet). Includes race and course details, photos, past results, and training tips.

100k event beginning in Florence, Italy. Includes general race details, photos, registration and contact information. English and Italian versions.

Magazine for ultramarathoners, with calendars, race results and reports, techniques and tips.

Oldest and largest 100-mile trail run in the U.S. starting at Squaw Valley. Course data, training run information, qualifying information, and preparation tips are included.

Six-day marathon across the Sahara Desert in Morocco with a description of the event, past results, registration details and pictures.

Membership application and extensive collection of links and information on events, trails, equipment, and race results.

Irish mountain running. Trails, races and links on the Island.

87km race in Durban, South Africa with information about the race, videos and photos, FAQs, chat room, results, route and history.

Resources, links, and general information. Includes runners` profiles, calendar, photographs and race reports.

Provides club news and events, including registration materials.

Seeks to promote ultramarathon running in Australia. Provides a race calendar, results, news, and links.

A series of mountain and trail races in Alberta, British Columbia, Ontario, and Quebec, Canada. Provides race details, registration, results, volunteerism, a message board, and news items.

Includes descriptions and links to events, photos and contact information.

Running, health, travel, and training, race results and race event calendars.

Information on a series of trail runs in the Bay Area of California. Race distances range from 5k to the marathon.

50km event held annually in Amman, Jordan with marathon, half-marathon and relay events. Registration, past results and contact information.