The First District is comprised of 20 of West Virginia's 55 counties. These 20 are listed below, followed in parentheses by their county seats. Click on each county's name to link to the latest data from the U.S. Census Bureau.

• Barbour County (Philippi)
  
• Brooke County (Wellsburg)
  
• Doddridge County (West Union)
  
• Gilmer County (Glenville)
  
• Grant County (Petersburg)
  
• Hancock County (New Cumberland)
  
• Harrison County (Clarksburg)
  
• Marion County (Fairmont)
  
• Marshall County (Moundsville)
  
• Mineral County (Keyser)
  
• Monongalia County (Morgantown)
  
• Ohio County (Wheeling)
  
• Pleasants County (St. Marys)
  
• Preston County (Kingwood)
  
• Ritchie County (Harrisville)
  
• Taylor County (Grafton)
  
• Tucker County (Parsons)
  
• Tyler County (Middlebourne)
  
• Wetzel County (New Martinsville)
  
• Wood County (Parkersburg)