We do not currently know of any antonyms for Roman mile.
The noun Roman mile is defined as:
An ancient Roman unit of itinerant distance of 1,000 paces (mille passus, hence also "mile" from Latin mille, "1,000"). Indirectly standardized to 5,000 Roman feet by Agrippa in 29 BC. In modern times, Agrippa's Imperial Roman mile is empirically estimated to have been around 1,481 meters (1,620 yards, 4,860 English feet).