Marsh had been doing the job at the Dog & Duck on a temporary basis after he stepped up from being the assistant-manager following the departure of Stuart Goosey.
But the Doughboys have now confirmed that Marsh and his assistant Gary Petts will lead the club into next season.
Wellingborough, like every other local ChromaSport United Counties League club, will simply be hoping they can return to action on Saturday.
The final five games of the Doughboys' Premier Division season are all away from home.
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They won their last six home matches of the campaign but Marsh’s team will now need to get over their travel sickness during the run-in.
Wellingborough haven’t won on the road since a 3-1 success at Peterborough Northern Star on November 25 and will look to put that right when they head to fifth-placed Deeping Rangers this weekend.
Desborough Town face a tough assignment on Saturday when they travel to take on table-topping Yaxley.
The leaders currently hold a six-point advantage at the summit but second-placed Wisbech Town have three games in hand.
At the other end of the table, it’s shaping up to be another key weekend for struggling Whitworth.
The Flourmen have lost their last five matches and they will hope to end that run when they entertain Peterborough Northern Star, who also sit in the lower half.
Rothwell Corinthians’ season is petering out into a mid-table finish after a poor second half of the season.
They are on the back of three defeats in a row as they take on Sleaford Town at Sergeants Lawn this weekend.
The only local club to play a game last weekend were Burton Park Wanderers.
Their Division One encounter at Olney Town went ahead last Saturday and Wanderers twice came from behind to claim a 2-2 draw thanks to Paul Caswell’s brace.
Should the weather hold, Wanderers face the toughest of examinations this weekend when they host leaders Pinchbeck United who require another eight points from their final seven matches to claim the title.
Raunds Town can’t afford to slip up as they try to keep the pressure on second-placed Potton United in the battle for the other promotion place and the Shopmates take on Lutterworth Athletic at Kiln Park.
Irchester United also have home advantage this weekend as they take on eighth-placed Bourne Town at Alfred Street.