Tewksbury Federal Credit Union Field of Membership is as follows: Anyone who lives, works, worships or attends school in the Town of Tewksbury, Massachusetts Retired former town employees and their surviving widows or widowers Relatives of TFCU members are eligible to join by federal regulation if they are a spouse, domestic partner, child, sibling, parent, grandparent, or grandchild of a member. This includes stepchildren, stepparents, step siblings, and adopted children