France's frontier with Belgium
Its function remains uncertain: it may have been conceived as a defensible barrier, or, more probably, as a well-defined frontier between two countries.
an end to frontier controls
Many times public houses were the first erected structures around which frontier towns grew.
Settling the American frontier was a matter of private choice, as were decisions about moving on.
The frontier between India and Pakistan ran through the Sikh homeland of the Punjab.
Attempts by the British to restrict further expansion into the western frontier constituted one of the factors contributing to the Revolution.
The high Andes peaks constitute its natural frontier with Bolivia and Argentina.
After the reductions following that war, the Army returned to its frontier outposts.
But perhaps it would be fairer to suggest that it was the frontier that failed the settlers.