Don’t send it USPS.
CLICK HERE FOR ADDRESSES
cut and paste
http://usgovinfo.about.com/gi/o.htm?zi=1/XJ&zTi=1&sdn=usgovinfo&cdn=newsissues&tm=15&f=00&tt=2&bt=0&bts=1&zu=https%3A//www.senate.gov/general/contact%255Finformation/senators%255Fcfm.cfm