The United States Postal Service Willis Post Office is located at 609 North Campbell Street."Post Office Location - WILLIS." United States Postal Service. Retrieved on December 8, 2008.
the uniteD states POsTal sErvICE wiLlis pOsT oFfIce is LocatEd At 609 nortH cAmpbELl STreEt."pOsT offIce locatIon - WiLLis." uniTed sTaTes postaL ServICe. ReTRIEved on DEcEmBeR 8, 2008.