The England side, who will fly out to North American on Monday, will play three matches in Salt Lake City against Canada, France and USA.
Young forward Gill, a former Eggbuckland Community College pupil, has one full international cap to her name, having made her debut in February against Scotland in the Six Nations. She had previously captained the England Under-20 side.
Also included in the tour party is former University of St Mark and St John prop Rochelle Clark, who is England’s most experienced player.
Both Gill and Clark play for top club side Worcester.
England lead coach Scott Bemand said: “This tour is an important opportunity for these girls to come together and play some of the top sides in the world.
“For those who haven’t been through the World Cup environment previously, they will experience everything there is around the tight turnaround of games and an away tour.
“We are really excited about the group of players travelling as it gives us the opportunity to further evolve our style of play.”
England will play Canada on July 1, France on July 5 and the USA on July 9.
England Women squad to travel to USA
Zoe Aldcroft (Darlington Mowden Park) (uncapped)
Sarah Bern (Bristol) (uncapped)
Bianca Blackburn (Worcester) (13 caps)
Lauren Cattell (Saracens) (18 caps)
Lotte Clapp (Saracens) (7 caps)
Rochelle Clark (Worcester) (110 caps)
Amy Cokayne (Lichfield) (13 caps)
Victoria Cornborough (Richmond) (14 caps)
Lark Davies (Worcester) (1 cap)
Courtney Gill (Worcester) (1 cap)
Sarah Hunter (Bristol) (78 caps)
Megan Jones (Bristol) (1 cap)
Laura Keates (Worcester) (49 caps)
Heather Kerr (Darlington Mowden Park) (6 caps)
Ceri Large (Worcester) (47 caps)
Ruth Laybourn (Darlington Mowden Park) (16 caps)
La Toya Mason (Darlington Mowden Park) (54 caps)
Katie Mason (Bristol) (10 caps)
Alex Matthews (Richmond) (21 caps)
Harriet Millar-Mills (Lichfield) (31 caps)
Isabelle Noel-Smith (Bristol) (17 caps)
Fiona Pocock (Richmond) (26 caps)
Amber Reed (Bristol) (29 caps)
Leanne Riley (Saracens) (7 caps)
Tamara Taylor (Darlington Mowden Park) (91 caps)
Lydia Thompson (Worcester) (22 caps)