Three town councils have joined together to show their united support for the Rushden Lakes development.
The leaders of Rushden, Higham Ferrers and Irthlingborough town councils have taken the unusual step of joining forces to back the scheme.
A final decision will be made at an inquiry in June.
Rushden Town Council leader Cllr Sarah Peacock said: “It’s important that everyone comes together, it’s for the community to all join together to support what’s being proposed.
“Rushden Lakes would bring so much to the area, not just retail but also leisure and jobs. This is for future generations. It’s time now to kick-start the economy.”
Irthlingborough Town Council leader Cllr John Farrah said: “We have joined together so that it’s a united front – everyone who is supporting it ought to join together. It’s important because of the job opportunities, it’s also going to clear up a derelict site, and give people a choice of shopping and leisure facilities.”
Cllr Derek Lawson, leader of Higham Ferrers Town Council, said: “We are in favour of this because of the employment element. We have got 2,000 jobs at risk and that is very important for the three towns, and for the wider area.
“This is something we have waited for, for a long time.”