Sussex will be playing in the first division of the National League next season.
The Sharks clinched promotion last night without playing when Leicestershire lost by six wickets to Derbyshire at Grace Road.
It means Sussex will definitely finish in one of the top three places.
Only two counties, second-placed Durham and Warwickshire, can overtake their points tally of 46.
Sussex will go up as champions if they win their remaining games against Kent and Yorkshire, but in reality one victory may be enough because of their superior net run rate.
Chris Adams' men have led the table for much of the season and they recovered from a mini-slump when they lost three in a row to win their last three games.
Director of Cricket Peter Moores said: "We've deserved promotion because I think we have been the most consistent side all season. But it would be nice to finish the job by claiming the title - that's what the players will want now."
Sussex will be playing in the top flight for only the second time since the split to two divisions in 1998. They won promotion the following year but only stayed up for one season.
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