Welcome to CornerStone Staffing, one of the leading staffing agencies in Addison, TX. Best in Staffing Services. Best in Career Placement. The Best Choice for You! CornerStone Staffing – Addison is located at the corner of Beltline & the Dallas North Tollway. Located only a few minutes north of the Galleria Dallas, we are conveniently located in the center of Addison’s excellent restaurants & shopping. The Addison recruiting team is dedicated to finding and qualifying the best clerical, customer service, and accounting candidates in the North Dallas area.