According to the Authority record for the name McDill in the Library of congress catalog, the names connected to this venerable surname are: MacDill, Madill, Medill, and Medille. No mention is made of McDilda, Dilda, or Dill, for what it's worth.The L.C. record also cited a monograph by L.A.M. Dingwall called The Descendents of Benjamin Madill, dated 1983. Columbia University catalog has a record ofa book called An American Dynasty which makes mention of some notable McDills. Is anyone familiar with either of the books mentioned above?