in Williamsburg, VA should be pronounced "Montichello" like the name of the musical instrument.This street
in Charlottesville, VA should also be pronounced the same way as above.
To be honest, anywhere in the United States where this name is used it should be pronounced that way. This is the proper pronunciation that can be found with a simple Google search. However, local preference outside of these two areas varies, so at this time just these two examples need to be changed.