south of ...; ... and southward
Suffix attached to a place name or area to indicate the region south of that reference point, or including that point and extending southward.
This train line is heavily delayed south of Tokyo.
The start of the rainy season was announced for the Kanto region and southward.
以西 means 'west of ...' or '... and westward'.
Compound of 以 (i, 'from; by means of') and 南 (nan, 'south'). The 以 prefix indicates a directional boundary or range.