More than 1,000 competitors will be on the start line for the Kielder Marathon.
Former Olympic athlete and world record holder Steve Cram will be there to cheer them on as they prefer for a race dubbed 'Britain's most picturesque marathon' - 26.2miles around Kielder Water in Northumberland
The Kielder Junior Runs will start at 11am at Leaplish Waterside Park - 45 minutes after the main race.
Yesterday, competition was fierce for the the Kielder 10km and Run bike Run events - part of the marathon weekend.
The annual Jack Charlton Disabled Anglers Cup has been held on Kielder Water in Northumberland.
Whilst busy fishing, the former England player, looked ahead to the upcoming World Cup.
Kielder Water and Forest Park, the home of the biggest man-made lake in northern Europe, has been awarded the prestigious Gold Award for Best Tourism Experience at the Visit Britain awards - which were held last night.
The Northumberland park also has the biggest working forest in England, covering 250 square miles.
Plans for a "mega-canal" connecting Northumberland with London have been put forward to the Government by multinational company AECOM.
The idea is to provide water supplies to southern England, but AECOM say it could also solve many transport, power and agricultural problems.
The 24 metre wide waterway would draw water principally from the Kielder reservoir in Northumberland and the Lake District in Cumbria, using gravity to continue its flow south.
It is estimated that the project could cost £14 billion.
Plans for a huge canal, connecting Northumberland and Cumbria with London, are being drawn up by an American company. The idea is to provide water supplies for the South of England.
The canal would begin by drawing water from the Kielder reservoir in Northumberland, and would then go west into Cumbria, using gravity to continue its flow further south to Leeds, Birmingham and onto London.
Aecom, the engineering company behind the London 2012 Olympic Park, says it could cost £14billion.
Olympic gold medalist Steve Cram is launching the fourth Kielder Marathon in the region today.
The sports star will be joined by Olympic decathalon gold medal holder Daley Thompson.
The weekend of events set to take place at Kielder Water will be held in October and will also include a 10 kilometre run, bike races and junior races.