In which Somerset, New Jersey community did President Warren G.
Harding sign the peace treaty that ended World War 1?

Dear Kck, 

The answer is Raritan Borough. 

" Raritan Borough is also the site where President Harding signed the
documents formally ending World War I in 1921." (SOURCE: Indulge
Yourself in Somerset County?s Culture, PDF Document, Somerset Business
Partnership Website,
<http://www.somersetbusinesspartnership.com/tourism/tourism-questions.pdf>).

I hope this answers your question. Please contact me if you need any
clarification on this answer before you rate it. My search terms:
["President Warren G.  Harding" "peace treaty" Somerset, New Jersey]