Callum Howe put Harrogate in front when he nodded in after Liam Kitching’s header had come back off the bar.
Jack Muldoon doubled the advantage just before the break, slotting home after being played in on goal by Joe Leesley.
Maidstone’s best chance to get back in the game fell to Shamir Mullings, but his header was deflected on to the bar.
An awful first-half cost FC Halifax Town dear as they lost 3-0 at Maidenhead.
Town conceded three goals in a game for the first time under Jamie Fullarton as two from the superb Josh Kelly and another from the also impressive Adrian Clifton put Maidenhead in complete command at half-time.
The Shaymen were never in control of the contest and all too soon had too much work to do to salvage anything form it.
Early shots at goal from Clifton and Harold Odametey set the tone from the hosts, who also went close through giant centre-back Ayo Obileye’s header.
Kelly’s first could hardly have been simpler, as he nodded in a right-wing cross at the far post.
The driver of the train that shuttled behind the main stand at York Road must have been listening to the match, as it’s horn was honked shortly after Clifton’s goal, when he pounced as another cross wasn’t cleared to rifle in from 12 yards.
All signals were pointing to a Town defeat.
After that, Johnson kept out another shot, and Clifton volleyed wide, with The Shaymen unable to muster a response.
Town have defended with real commitment, determination and desire so far this season, but their defence looked uncharacteristically vulnerable here, especially to crosses and to pace. Both of which Maidenhead exploited.
By the time Kelly got his second and Maidenhead’s third, it already looked game over. Once the striker latched onto a flick on by Clifton to a long pass, there was no catching him, and he stayed cool to finish past Johnson.
Edwards had a chance for a consolation goal with a quarter of an hour to go, but couldn’t connect properly with Jordan Preston’s cross, before Clarke had a header cleared off the line a few minutes later.
The outstanding Obileye was then sent-off in the 90th minute for a second booking.