The 22-year-old Exeter Chiefs player, who only made his full England debut less than two weeks ago, has got the nod ahead of the more experienced Luther Burrell.
Utility back Slade started playing rugby at Ivybridge RFC and starred for the Plymouth College team that reached the quarter-finals of the Daily Mail Cup in 2011.
He then spent two seasons playing for Plymouth Albion under Graham Dawe and Nat Saumi before forcing his way into Exeter Chiefs’ first team squad.
Slade is joined in the England World Cup squad by fellow former Albion player Jack Nowell.
The last time England had two former Plymouth players in a World Cup squad was when they won the tournament in 2003. Props Julian White and Trevor Woodman both featured in that successful squad.
England head coach Stuart Lancaster said after announcing his squad: “It’s really positive that we have such depth and options to choose from. Selection wasn’t easy and it is tough to leave anyone out but it’s important to stress that the players not in this group are still part of our wider squad and could come in at any point.
“After 10 weeks in camp we have made our final selection of players and we believe we have a great group to take us into the tournament. With three weeks to go before we play Fiji we believe we are in good shape as we head into next Saturday’s game against Ireland.
“As the excitement builds around the tournament we are looking forward to the country getting behind England and we know this group of players will represent the nation with pride.”
England Rugby World Cup squad
Kieran Brookes (Northampton Saints, 10 caps)
Dan Cole (Leicester Tigers, 51 caps)
Joe Marler (Harlequins, 32 caps)
Mako Vunipola (Saracens, 22 caps)
David Wilson (Bath Rugby, 43 caps)
Jamie George (Saracens, 1 cap)
Rob Webber (Bath Rugby, 13 caps)
Tom Youngs (Leicester Tigers, 23 caps)
George Kruis (Saracens, 8 caps)
Joe Launchbury (Wasps, 23 caps)
Courtney Lawes (Northampton Saints, 39 caps)
Geoff Parling (Exeter Chiefs, 24 caps)
James Haskell (Wasps, 60 caps)
Ben Morgan (Gloucester Rugby, 28 caps)
Chris Robshaw (capt, Harlequins, 38 caps)
Billy Vunipola (Saracens, 18 caps)
Tom Wood (Northampton Saints, 37 caps)
Danny Care (Harlequins, 52 caps)
Richard Wigglesworth (Saracens, 22 caps)
Ben Youngs (Leicester Tigers, 48 caps)
Owen Farrell (Saracens, 30 caps)
George Ford (Bath Rugby, 12 caps)
Brad Barritt (Saracens, 22 caps)
Sam Burgess (Bath Rugby, 1 cap)
Jonathan Joseph (Bath Rugby, 12 caps)
Henry Slade (Exeter Chiefs, 1 cap)
Mike Brown (Harlequins, 38 caps)
Alex Goode (Saracens, 18 caps)
Jonny May (Gloucester Rugby, 15 caps)
Jack Nowell (Exeter Chiefs, 9 caps)
Anthony Watson (Bath Rugby, 10 caps)