The 26-year-old previously spent four years in Sweden with Eskilstuna United, who she captained last season.
"I'm really excited to have signed for Notts, it's a great club with lots of history," she told Notts' club website.
Manager Rick Passmoor added: "Louise brings with her a wealth of experience, including Champions League football."
Women's Super League One club Notts County Ladies have signed Republic of Ireland centre-back Louise Quinn, subject to international clearance.