For years, playing The Oregon Trail required original hardware or DOS emulation software. However, the game has been kept alive by, and made widely accessible through, "unblocked" versions, which allow school and office employees to bypass network restrictions to play browser-based games.
Several unblocked game hubs (like classicreload.com or playclassic.games ) host the original black-and-green vector version. Search for “Oregon Trail unblocked 1985.” This version is so old that most modern filters ignore it entirely.