Rashi on Numbers 35:29/רש"י על במדבר ל״ה:כ״ט

1בכל מושבתיכם [AND THESE THINGS SHOULD BE AN ORDINANCE OF JUSTICE FOR YOU] IN ALL YOUR DWELLINGS — This teaches that the "minor Sanhedrin" functions outside the Land as long as there is [the main] one functioning in the Land of Israel [namely, while the Temple stood].(Makkot 7a)