"Voluntary association produces the free market - where each person can choose among a multitude of possibilities." – Harry Browne 

1. American Nurses Association (ANA) - Website ANA is a national professional association for registered nurses in the United States. It aims to advance the nursing profession by promoting high standards of nursing practice, projecting a positive and realistic view of nursing, and lobbying the Congress and regulatory agencies on health care issues affecting nurses and the public. 

2. American Association of Nurse Practitioners (AANP) - Website AANP is an American organization formed to provide nurse practitioners with a unified way to network and advocate for their issues. They represent the interests of the more than 290,000 licensed NPs in the U.S. 

3. American Association of Critical-Care Nurses (AACN) - Website AACN is the largest specialty nursing organization in the world, representing the interests of more than 500,000 nurses who are charged with the responsibility of caring for acutely and critically ill patients. 

4. Emergency Nurses Association (ENA) - Website ENA represents the interests of emergency nursing globally with more than 50,000 members. It's dedicated to defining the future of emergency nursing and emergency care through advocacy, expertise, innovation, and leadership. 

5. American Psychiatric Nurses Association (APNA) - Website APNA is a professional association of psychiatric–mental health nurses. It promotes mental health care, literacy, and policy worldwide. 

6. Oncology Nursing Society (ONS) - Website ONS is a professional association of more than 35,000 members committed to promoting excellence in oncology nursing and the transformation of cancer care. 

7. National Association of Pediatric Nurse Practitioners (NAPNAP) - Website NAPNAP is the professional association for pediatric nurse practitioners (PNPs) and all pediatric-focused advanced practice registered nurses (APRNs). 

8. American Organization for Nursing Leadership (AONL) - Website AONL is a national organization and subsidiary of the American Hospital Association, focused on nursing leadership development and advocacy. 

9. National Black Nurses Association (NBNA) - Website NBNA's mission is to provide a forum for collective action by African American nurses to investigate, define and advocate for the health care needs of African Americans. 

10. American Association of Neuroscience Nurses (AANN) - Website AANN is committed to working for the highest standard of care for neuroscience patients by advancing the science and practice of neuroscience nursing. 

11. American Association of Occupational Health Nurses (AAOHN) - Website AAOHN is a professional association dedicated to advancing the health, safety, and productivity of domestic and global workforces by providing education, research, public policy, and practice resources for occupational and environmental health nurses. 

12. American College of Nurse-Midwives (ACNM) - Website ACNM is the professional association representing certified nurse-midwives and certified midwives in the United States. It promotes excellence in midwifery education, clinical practice, and research. 

13. American Holistic Nurses Association (AHNA) - Website AHNA is a non-profit membership association serving more than 4,500 members and 130 local and online chapters across the U.S. and abroad. It's dedicated to holistic nursing. 

14. American Nephrology Nurses Association (ANNA) - Website ANNA is a community of professionals dedicated to advancing nephrology nursing practice and positively influencing outcomes for patients with kidney disease. 

15. American Society of PeriAnesthesia Nurses (ASPAN) - Website ASPAN represents the interests of nurses who specialize in preanesthesia and postanesthesia care, ambulatory surgery, and pain management. 

16. Association of Pediatric Hematology/Oncology Nurses (APHON) - Website APHON provides and promotes expert practice in pediatric hematology/oncology nursing to its members and the public at large. 

17. Association of Rehabilitation Nurses (ARN) - Website ARN is a professional healthcare association dedicated to promoting and advancing professional rehabilitation nursing practice through education, advocacy, collaboration, and research to enhance the quality of life for those affected by disability and chronic illness. 

18. Association of Women's Health, Obstetric and Neonatal Nurses (AWHONN) - Website AWHONN is a 501(c)3 nonprofit membership organization that promotes the health of women and newborns. 

19. Dermatology Nurses' Association (DNA) - Website DNA is a professional nursing organization comprised of a diverse group of individuals committed to quality care through sharing knowledge and expertise. 

20. National Association of Neonatal Nurses (NANN) - Website NANN is a community of registered nursing professionals who care for infants born with a variety of health challenges and surgical problems. 

21. National Association of School Nurses (NASN) - Website NASN improves the health and educational success of children and youth by developing and providing leadership to advance school nursing practice by specialized registered nurses. 

22. National League for Nursing (NLN) - Website NLN is the premier organization for nurse educators, offering faculty development, networking opportunities, testing services, nursing research grants, and public policy initiatives. 

23. Oncology Nursing Society (ONS) - Website ONS is a professional association of more than 35,000 members committed to promoting excellence in oncology nursing and the transformation of cancer care. 

24. Pediatric Endocrinology Nursing Society (PENS) - Website PENS is committed to the development and advancement of nurses in the art and science of pediatric endocrinology nursing. 

25. Sigma Theta Tau International Honor Society of Nursing (Sigma) - Website Sigma is the second-largest nursing organization in the world with approximately 135,000 active members who are recognized leaders and scholars who are invited to join the society. 

26. Society of Pediatric Nurses (SPN) - Website SPN is an organization dedicated to promoting the optimal health of children through leadership in pediatric healthcare nursing practice, education, research, and advocacy. 

27. Transcultural Nursing Society (TCNS) - Website TCNS aims to provide nurses and other healthcare professionals with the knowledge base to practice culturally competent care and improve patient outcomes. 

28. Wound, Ostomy and Continence Nurses Society (WOCN) - Website WOCN is a professional nursing society that supports its members by promoting educational, clinical, and research opportunities to advance the practice and guide the delivery of expert health care to individuals with wounds, ostomies, and incontinence. 

29. American Association for Men in Nursing (AAMN) - Website AAMN aims to provide a framework for nurses, as a group, to meet, discuss, and influence factors, which affect men as nurses. 

30. International Society of Nurses in Cancer Care (ISNCC) - Website ISNCC represents a global community of cancer nurses shaping health policy in cancer care, through advancing science and promoting partnerships 

31. American Assembly for Men in Nursing (AAMN) - Website AAMN is a national organization that provides a framework for nurses to discuss and influence factors that affect men pursuing nursing as a career. 

32. National Student Nurses' Association (NSNA) - Website NSNA is a nonprofit organization for students enrolled in associate, baccalaureate, diploma, and generic graduate nursing programs. It aims to promote the professional development of future registered nurses and facilitate their entrance into the profession. 

33. American Forensic Nurses (AFN) - Website AFN is a professional organization for nurses who apply nursing science to public or legal proceedings. It provides certification, education, and leadership in forensic nursing. 

34. National Gerontological Nursing Association (NGNA) - Website NGNA is dedicated to the clinical care of older adults across diverse care settings. Members are registered nurses, licensed practical/vocational nurses, student nurses, and others interested in the field of gerontological nursing. 

35. Association for Radiologic & Imaging Nursing (ARIN) - Website ARIN promotes the role of nurses in imaging and radiologic services by providing resources and information to help them excel in this field. 

36. Academy of Medical-Surgical Nurses (AMSN) - Website AMSN is a community of medical-surgical nurses that supports and fosters the professional growth and development of its members. 

37. National Association of Orthopaedic Nurses (NAON) - Website NAON is a nonprofit, volunteer-run organization that enhances the lives and careers of orthopaedic nurses. It provides continuing education, research grants, certification, and networking opportunities. 

38. National Association for Home Care & Hospice (NAHC) - Website NAHC is a nonprofit organization that represents the nation's 33,000 home care and hospice organizations. 

39. American Association of Heart Failure Nurses (AAHFN) - Website AAHFN is a specialty organization dedicated to advancing nursing education, clinical practice, and research to improve heart failure patient outcomes. 

40. Hospice and Palliative Nurses Association (HPNA) - Website HPNA is a professional nursing organization dedicated to promoting excellence in palliative nursing through leadership development, education, and the dissemination of research. 

41. American Association of Nurse Practitioners (AANP) - Website AANP is a community of exceptional nurse practitioners (NPs) that advocates for their role in healthcare and empowers them to provide high-quality, patient-centered care. 

42. American Psychiatric Nurses Association (APNA) - Website APNA is a professional association for nurses specializing in psychiatric and mental health care. It promotes mental health care, literacy, and policy worldwide. 

43. American Association of Critical-Care Nurses (AACN) - Website AACN is the largest specialty nursing organization in the world, representing the interests of more than 500,000 critical care and acute care nurses. 

44. Emergency Nurses Association (ENA) - Website ENA represents global emergency nursing through leadership, research, education, and advocacy. It's committed to patient safety and care in emergency settings. 

45. American Association of Nurse Anesthetists (AANA) - Website AANA is a professional association representing more than 50,000 Certified Registered Nurse Anesthetists (CRNAs) and student registered nurse anesthetists. 

46. American Nursing Informatics Association (ANIA) - Website ANIA is dedicated to advancing the field of nursing informatics through communication, education, research, and professional activities. 

47. American Association of Legal Nurse Consultants (AALNC) - Website AALNC is a non-profit membership organization dedicated to the professional enhancement and growth of registered nurses practicing in the specialty area of legal nurse consulting. 

48. Nursing Organizations Alliance (NOA) - Website NOA is a coalition of nursing organizations united to create a strong voice for nurses. 

49. American Association of Occupational Health Nurses (AAOHN) - Website AAOHN is dedicated to advancing the health, safety, and productivity of domestic and global workforces by providing education, research, public policy, and practice resources for occupational and environmental health nurses. 

50. American Association of Diabetes Educators (AADE) - Website AADE is a multi-disciplinary professional membership organization dedicated to improving diabetes care through innovative education, management, and support. 

 Please note that the names, scopes, and websites of these associations can change over time, and it is always best to refer directly to the association's website for the most up-to-date and accurate information.