Don Travers and Karen Alexander are favourites to defend their titles in the third Castleward Challenge Half Marathon.
The ‘Born 2 Run’ event is being held in the grounds of the stately home near Strangford.
Travers showed that he is in top shape with victory in the Dune Half Marathon between Dundalk and Newry and he is a master of racing on mixed surfaces.
Richard Coey and Simon Reeve, second and third respectively last year, will be prominent again along with Stuart Paulin and Mark McKinstry while there is a chance that Duncrue champion Brendan Teer will compete.
Karen Alexander won comfortably last time from Julie Murphy and a repeat looks to be on the cards.
The race starts in the shadow of the stately mansion and covers forest trails, open pastures and paths on the edge of Strangford Lough.
Registration is at the marquee in the main courtyard. The half marathon and walk both start at 10am with the 10K at 10.45am.
Meanwhile, Stephen Duncan is hot favourite for Saturday’s Gortin 10K Road Race. The Northern Ireland Master champion, who came fourth in the Omagh Half Marathon was second to Keith Shiels in Gortin last year but should go one better this time.
Fergus McGirr, Paul Barbour, Damien Cox and possibly Alan Bogle will all feature with Omagh likely to take the team prize.
Ladies champion Sara Moore is now at college in America but there can still be an Omagh winner through Michelle Sturm, who will battle with last year’s runner up Mairaid McCann.
The 10K race plus 5K fun run and walk start from the Ulster Bank in Main Street at 12 noon.
In other news Athletics Northern Ireland have selected strong teams for the three miles mini marathon in London, which is part of the Virgin London Marathon.
Conor Christie and Paddy Robb lead the Under 17 Boys while the very strong Under 15 side includes Christy Conlon, James Edgar, Eoin McCann and Patrick McNiff.
The full sides are: U17 Boys, Conor Christie, Paddy Robb, Jonathan Whan, Conal McCambridge, James Smyth and Ronan O’Fril. U15 Boys, James Edgar, Christy Conlon, Eoin McCann, Patrick McNiff, Ciaran Brolly and Peter Fegan.
U13 Boys, Peter Murray, Kian Bittles, Tony McCambridge, Sam Ross, James O’Farrell and Niall Connolly.
U17 Girls, Lois Hagen, Eilish Flanagan, Catriona McGloin, Zoe Carruthers, Aoife McSherry and Toni Moore.
U15 Girls, Madison Bowyer, Edel Monaghan, Emma Hutchinson, Abigail McBroom, Caelainn McQuaid and Daire McCartan.
U13 Girls, Olivia Nelson, Enya Haigney, Kate Gurley, Rachel Brown, Niamh Heaney and Mollie Brown.