The Premier League leaders, stretching their lead to six points, produced another exhilarating performance to stun shell-shocked Manchester City in the top-of-the-table clash at the Etihad stadium.
Poor marking allowed defender Huth to sweep in Mahrez's free kick, via a deflection off Martin Demichelis, after three minutes.
Playmaker Mahrez finished off a swift break to score his 14th league goal of a hugely impressive season and double Leicester's lead three minutes into the second half.
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Huth headed in a corner on the hour to make it 3-0, proving that Leicester, on 53 points from 25 games, have the quality and belief to make a sustained challenge.
Sergio Aguero headed a late consolation for the hosts who learned this week that Pep Guardiola will replace Manuel Pellegrini in charge next season.
Leicester face another significant test of their credentials next weekend at Arsenal and manager Claudio Ranieri wants his side to enjoy the moment.
"It is crazy. It is a crazy Premier League. It is a good result, the players played very well. We were never afraid. We wanted to win here," the Italian told BT Sport.
"We play every match as though it is the last match. Now we are very, very confident and it is important to think about Arsenal, we are ready to fight there."
As they have done all through a season that continues to confound those waiting for Leicester's shock title assault to fade away, their counter-attacking brilliance and set-piece strength made a mockery of the team who boasted the best home record in the league.
They made the perfect start when Huth, given his debut by Ranieri when a 17-year-old at Chelsea, took advantage of poor marking to convert Mahrez's low cross.
With swift attacks menacing City's defence, Leicester tore into the hosts and Joe Hart thwarted Mahrez and top scorer Jamie Vardy.
City countered with Aguero testing Kasper Schmeichel and the hosts grew into the game as the first half wore on.
Hopes of mounting a fightback after the break were quickly extinguished, however, when Leicester attacked from deep in their half on the break, the impressive N'Golo Kante fed Mahrez and the Algerian international advanced into the box to fire past Hart.
Schmeichel kept out Fernando's close-range header before the towering Huth rose above City's defenders to loop a header beyond Hart to make it 3-0.
Hart denied Vardy a fourth and although City did break through late on, the hosts were well beaten.
(Reporting by Justin Palmer, editing by Ed Osmond)
