Do not go out on Shabbos beyond the Sabbath limit.
“Let no man go out of his place on the seventh day” Shmot 16:29
This means going outside the town beyond 12 mils (approximately 12 km), corresponding the camp of the Israelites in the wilderness, even by one hand breath, is to be lashed for disobedience.
The view of the Rif and Rambam is that going beyond 2000 cubits (approximately 1km) which is the open land around the town is to be punished by whiplashes for disobedience.
The 2000 cubits are considered as square cubits to get the extra distance from the corners.
Within the city it is permissible to walk everywhere even if it is very large.
This applies at all places at all times for men and women.