In frontier areas they are critical to our ability to win access.

Its soldiers probably saw action in local wars against the Indian tribes of this frontier area.

This was especially true in frontier areas occupied by the army.

This was a building built for defense against primarily Indian attacks in frontier areas.

Others were able to buy land and farm in frontier areas further from white control.

Supplying the military posts in the frontier area was difficult.

Only the extreme northwestern part of the state remained a frontier area.

This is far more than can be said of many frontier areas where international oil companies are accustomed to doing business.

This increased the importance of exploration and development projects in frontier areas.

Jones was attracted to frontier areas, an interest reflected in his work.