The 21-year-old, capped twice for the Northern Ireland Under-21s, played 11 games for the League Two side during a six-month stay at Meadow Lane in 2017-18.
According to BBC Sport, Brighton have not included a recall option for Hall, who has been with the Amex Stadium outfit since June 2016.
"Ben's move to Notts County last season proved to be a successful one for all parties concerned, so this renewed loan made sense," Brighton Under-23s coach Simon Rusk told the official club site.
"It was great to see Ben getting some first-team football under his belt, as he became more accustomed to the physical demands of senior football in England.
"We wish Ben the best of luck at Notts County for the season ahead, and we'll certainly monitor his progress during his time away."
Brighton recently activated an option to extend Hall's contract by another year after originally signing the Enniskillen-born player from Scottish club Motherwell.