The 22-year-old will look to gain further experience of first-team football and continue his development during his time with the Birkenhead club, who compete in EFL League One.
It will be the fourth loan of the left-back’s career so far, following spells at Wolverhampton Wanderers, Leeds United and Scunthorpe United.
The Manchester-born Academy graduate has made 14 senior appearances for United to date, all of which came during the 2015/16 campaign.
Borthwick-Jackson becomes the ninth Red to embark on a loan move for the term ahead, following Kieran O’Hara (Burton Albion), Dean Henderson (Sheffield United), Alexis Sanchez (Internazionale), Chris Smalling (AS Roma), Alex Fojticek (Stalybridge Celtic), Joel Pereira (Hearts), George Tanner (Morecambe) and Aidan Barlow (Tromso).