On May 21, 1974, the electorate approved a Home Rule Charter, which took effect on January 1, 1975; as such, the community is no longer governed under the provisions of the Pennsylvania Township Code. Mount Lebanon became one of the first municipalities in Pennsylvania to adopt a home rule charter. In the charter, the official name of the municipality became Mt. Lebanon, Pennsylvania; the word Mount is abbreviated in all government documents, although the U.S. Postal Service continues to use Mount.