Anne Sullivan is known for being Helen Keller's instructor.
NOTOC. This is a list of the Pennsylvania state historical markers in York County .. This is intended to be a complete list of the official state historical markers placed in York County , Pennsylvania by the Pennsylvania Historical and Museum Commission -LRB- PHMC -RRB- .. Pennsylvania Historical and Museum Commission. Pennsylvania Historical and Museum Commission. The locations of the historical markers , as well as the latitude and longitude coordinates as provided by the PHMC 's database , are included below when available .. There are 62 historical markers located in York County .