A comfortable victory at Home Park and results elsewhere have sealed the Seagulls' first promotion since 1987-88.
Early goals by Paul Brooker and the unstoppable Bobby Zamora made sure of the points for Micky Adams' men.
The players and staff then had an agonising few seconds to wait for confirmation that Hartlepool had lost 1-0 at home to Hull and Rochdale drawn 0-0 at Macclesfield.
That allowed the celebrations to begin in front 1,300 jubilant Seagulls supporters.
Adams carried a banner on to the pitch which proclaimed 'we are going up'.
The Seagulls can now look forward to a promotion knees-up against Darlington at Withdean on Monday.
They can also concentrate all their efforts in the remaining six matches on clinching their first championship since 1964-65.
Albion's ninth away win of a memorable campaign was rarely in doubt once Brooker and Zamora had put them 2-0 up in 16 minutes.
A crowd of 7,490 saw Brooker fire the Seagulls in front with his fourth of the season in the third minute when the Plymouth defence failed to clear a Paul Watson corner.
Zamora doubled the lead 13 minutes later with his 27th of the season from close range after a Gary Hart shot had been blocked into his path.
Albion were in the comfort zone from that moment on.
Keeper Michel Kuipers was hardly troubled and Danny Cullip had another commanding match at the heart of the defence.
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