Upon the advice of Mr. Frank Henrich, President of the San Gabriel Valley Sister City Association, the GSCA decided that Glendora's first sister city should be located in Mexico due to the country's proximity and shared heritage.

In the summer of 1966, Dr. Vaniman attended the third International Convention of Cities in Puebla, Mexico. During this convention, Dr. Vaniman met with Mérida officials and discussed the possibility of becoming sister cities. Following this and several delegation visits, Glendora and Mérida officially became sister cities in 1968.

In 1977 for Glendora's Bicentennial, a mural painted by famous artist Manuel Lizama was donated by the city of Mérida and placed in the Bidwell Forum.

You can find a Mérida sister city marker sign on W. Gladstone Street, nearby the S. Lone Hill Avenue Intersection!

In the past, Glendora and Mérida hosted a vibrant high school exchange program where students could create deep bonds with one another and learn about each other's cultures.

While the sister city relationship has been inactive for some time, community members in both cities have been working to revitalize the connection between Glendora and Mérida, with the support of the local government.