Westmoreland County may refer to:

In Australia

• Westmoreland County, New South Wales
• the former name of Westmoreland Land District, Tasmania, Australia

In Canada

• Westmorland County, New Brunswick

In the United Kingdom

• The county of Westmorland, archaically spelt Westmoreland.

In the United States

• Westmoreland County, Pennsylvania
• Westmoreland County, Virginia
• Westmoreland County, Connecticut - A former county in Connecticut located in present-day Wyoming Valley