There are a few ways you can try 1. write to the hall of records in your state. 2. look for marrages in the county they were married in. 3 check the National Archives in your or their state. 4. Look for a family research center in your town they are run by the church fo latter day saints. 5 check with your own family , start with the older generation 1st . Look up old family BIBLES ,and old letters that family members may have stuffed away. Whenever you send off for information be sure you send the date of (birth,death,marrage,state they lived in ,the county,) this will be a big help if you know all of this information, also you may want to send a self stamped and your address envelope along with each request.