Defending champions Hampshire will play Lancashire in the quarter-finals of the Friends Life t20 competition.
The Royals ended the group stage with the best record, winning eight of their 10 games and topping the South Group with 17 points.
Lancashire finished second behind Nottinghamshire in the North Group, winning only five of their games and only narrowly edging Durham for second place.
Durham still made it through as one of the two best third-placed teams and their reward for progressing is a trip to Midlands/Wales/West Division winners Northants.
Nottinghamshire secured a home tie and Trent Bridge will host their clash with Essex, whose group campaign came to a losing end against Surrey - they only made it through when Middlesex failed to beat Hampshire on Wednesday evening.
Surrey, who won seven of their games to finish second behind Hampshire in the South Division, host Somerset who finished as runners up in the Midlands/Wales/West Division.
Quarter-final schedule (all games live on Sky Sports Ashes HD)
Tuesday, August 6 - Surrey v Somerset, the Kia Oval (4:15pm)
Tuesday, August 6 - Northants v Durham, County Ground (7:10pm)
Wednesday, August 7 - Hampshire v Lancashire, the Ageas Bowl (7:10pm)
Thursday, August 8 - Nottinghamshire v Essex, Trent Bridge (7:10pm)