About: Union Square is the largest credit union in the Texoma Area. We are here to serve you, our members, with the best products available and the most competitive rates around. We are people helping people. We are.... Your Financial Center of Choice! Mission: We are people helping people. Union Square Credit Union's field of membership is open to those who have the following common bond: Persons who live, work, worship or attend school in Archer, Baylor, Clay, Wichita or Wilbarger Counties, Texas; or Cotton or Tillman Counties, Oklahoma; Spouses of persons who died while within the field of membership of this credit union; Organizations of such persons. And members of the family of such persons.