I live only 25 miles from this location, but still had considerable difficulty finding a listing of cemeteries in Mexico, ME . . . but eventually was flooded with resources. There are only four cemeteries listed with the Maine Old Cemetery Association, P.O. Box 641, Augusta, Maine 04332; http://memoca.proboards92.com/index.cgi
Back Kingdom Cemetery, Mexico ME for which there is an inventory with pictures that has some Whitmans and Wings that might be of interest to you here: http://dixfieldcitizennews.net/TombstonesT/pattyhooper.html
Farrington-Morton Cemetery, Mexico ME
Frye Cemetery, Mexico ME
Mexico Corner Cemetery, Roxbury Road, Mexico, ME
Also, I found reverence too: Lithuanian Cemetery, Mexico, ME
After searching GoogleEarth I am convinced that Mexico Corner Cemetery is the one of interest to you. If you do a MapQuest search, for some reason it incorrectly identifies the corner that is at the center of Mexico as "Ridlonville" which is actually farther east on US Rt 2. The cemetery is just north of that main intersection of US Rt 2 & Roxbury Road, going north, and at the next intersection of Roxbury Road and Harlow Hill Road, there is a church with a churchyard cemetery.
I cannot say with absolute certainty that this is the one you seek, but all indications point to it. However, this is the link to the Town of Mexico website where you will find contact information, including e-mail links to the town manager and town clerk, both of whom can confirm for you I am sure. http://www.mexicomaine.net/html/townoffice.htm
Also, there is a local state senator who has a website of the area [Rumford-Mexico] which has considerable genealogical information on it that you may want to peruse if you are not already aware of it. He may be willing to help as well. http://freepages.genealogy.rootsweb.ancestry.com/~rum1800/
Hope this helps.
Bethel, Maine, USA