Nahki Wells' goal secured Huddersfield's Sky Bet Championship place for next season, though Rotherham are forced to wait after a 1-1 draw at New York Stadium.
Relegation was never on the cards but Wells cancelled out Greg Halford's early strike for the Millers to ensure their will be no unexpected late-season problems for the Terriers as they moved 11 points clear of the bottom three with three games to go.
The Millers' champagne mathematically remains on ice, though, as MK Dons' unlikely point at Sheffield Wednesday means they could still be overhauled on goal difference.
Another point or the Dons' failure to win in the next three games would mean Neil Warnock completes his SOS mission in South Yorkshire and the draw extends their unbeaten run to an impressive 10 matches.
Given that hot streak of form there was little surprise in seeing Warnock's men forge into a 10th-minute lead.
Huddersfield failed to clear a corner and it fell to Halford who smashed it in from close range, though the heavy deflection it took might interest the dubious goals panel.
The Millers had chances to add to their early advantage as Grant Ward tested Jed Steer's handling with a low shot while Richard Wood failed to connect properly with a free header eight yards out.
But the Terriers were handed a way back into the game midway through the second half.
First Ward was robbed of possession and when Wells was slipped in, his shot from 16 yards was too hot for Lee Camp to handle, though the Millers goalkeeper will be have been disappointed to see the ball squirm underneath him.
Despite dominating the rest of the first half, playing with speed and incision, the Terriers were unable to test Camp further and the Millers had the chance to regroup.
That allowed them to start the second half strongly and they put Town under pressure again as Richie Smallwood drove over from the edge of the area and Grant Ward put a glancing header wide.
Town's pace continued to cause the hosts trouble, though, and Joe Lolley's mazy run was palmed away well by Camp before the visitors mounted a late attempt to win the game.
Wells whistled a low drive from 20 yards just wide, the former Bradford striker then forced Camp into another save and Joel Lynch sent an effort from 35 yards wide.
The livewire Wells then had a goal disallowed as Huddersfield were unable to find that elusive breakthrough, but they will definitely be playing in the second tier next season.
Rotherham look certainties to follow, but they would have liked to get their business done this evening.