Mishneh Torah — Negative Mitzvot מצוות לא תעשה, Chapter 321
The full Hebrew text of Mishneh Torah, Negative Mitzvot, Chapter 321, with English translation by Maimonides (Rambam).
שלא להלך חוץ לתחום מדינה כהולכי דרכים בשבת, שנאמר "אל ייצא איש ממקומו" (שמות טז,כט).
Not to travel beyond the boundaries of a city on the Sabbath as travelers do, as [Exodus 16:29] states: "A person should not leave his place [on the Sabbath day]."