Which circuit has hosted a MotoGP race every year since 1949?

The circuit that has hosted the Dutch motorcycle Grand Prix throughout the modern world-championship era is TT Circuit Assen.

Assen’s connection with Grand Prix racing dates to 1949, the first season of the FIM Motorcycle Grand Prix World Championship. The Dutch TT became one of the championship’s defining events, and Assen is often nicknamed the “Cathedral of Speed.” Its original races used public-road layouts before a permanent circuit opened in 1955.

There is one important historical qualification: the event was cancelled in 2020 because of the COVID-19 pandemic. Thus, Assen is more precisely the only circuit to have hosted a motorcycle World Championship Grand Prix in every season from 1949 onward except 2020. The track remains a regular MotoGP venue, although the race moved from its traditional Saturday slot to Sunday in 2016.