Where would I find list of justices of peace early 1900 in simcoe county.

The Simcoe Branch of the Ontario Genealogical Society have outstanding resources for much of this province and they are really sharp. Also, info is available on micorofilm from the Simcoe County Archives and covers the period 1876 to 1905 and is called the Vernon Directory. It is possibly available in book form from the library.