Cobblers will be ball number 21 in the Carabao Cup first round draw on Thursday evening.
As in 2018, the draw will be split into northern and southern sections, but this year it takes place live from Morrisons, Colindale.
Conducting the draw will be former Liverpool winger John Barnes and ex-Arsenal fan favourite Ray Parlour, with fans able to watch live in store and also tune in to the Carabao Cup Facebook and Twitter pages.
The ties will be played week commencing August 12 with selected matches available live on Sky Sports.
Ball numbers: 1, AFC Wimbledon; 2, Birmingham City; 3, Brentford; 4, Bristol City; 5, Bristol Rovers; 6, Cambridge United; 7, Charlton Athletic; 8, Cheltenham Town; 9, Colchester United; 10, Coventry City; 11, Crawley Town; 12, Exeter City; 13, Forest Green Rovers; 14, Gillingham; 15, Ipswich Town; 16, Leyton Orient; 17, Luton Town; 18, Millwall; 19, MK Dons; 20, Newport County; 21, Northampton Town; 22, Oxford United; 23, Peterborough United; 24, Plymouth Argyle; 25, Portsmouth; 26, QPR; 27, Reading; 28, Southend United; 29, Stevenage; 30, Swansea City; 31, Swindon Town; 32, Walsall; 33, West Bromwich Albion; 34, Wycombe Wanderers.