Which Mario Kart game first featured the Rainbow Road track?

Super Mario Kart first featured the Rainbow Road track.

Rainbow Road debuted in the original Super Mario Kart for the Super Nintendo Entertainment System in 1992. It appeared as the fifth and final course of the Special Cup, establishing the series tradition of ending a game's main cup structure with a spectacular, difficult track set high above the ground.

The original course is famous for its lack of guardrails, sharp turns, and Star Thwomps that can knock racers off the narrow road. Unlike later versions, it has a relatively simple flat layout, but its unforgiving edges make even small steering mistakes costly. Rainbow Road became one of Mario Kart's signature locations and has returned in a distinct form in nearly every major installment.

Mario Kart 64, Wii, and Double Dash!! each contain their own Rainbow Road designs, but they came later. Later games also remade the SNES version as a retro course, which can make the debut year easy to overlook.