Trinity Methodist Church, the former Methodist Protestant Church of Harrington, was organized in 1880. Services were held in the afternoon in what was called "the old school house". located on the southwest corner of Dorman and Mechanic Streets. The first church was built in 1881 on land that is the present site of City Hall. In 1883, Harrington Mission (formerly Milford Mission) became Harrington Circuit. 

     On March 7, 1900, the church was incorporated in accordance with the Statute of the State of Delaware, providing for the incorporation of religious societies, or congregations of Christians. In April, 1903, it was decided to build a new church instead of putting a lot of money into the old one. The cornerstone was laid December 4, 1904. On October 15, the last services were held at the old church. On October 22 the members met at the old church and marched in a body to the new one for the dedication service.

     In 1926, Mrs. Elvia Sapp donated money to the church and the Sapp Memorial Building was constructed.

     Church bulletins were first used in the church in September 1932. 

     In 1939, the three large branches of Methodism united. It became necessary to choose a new name for the church. After 5 weeks weeks of voting the name was changed from Methodist Protestant Church to Trinity Methodist Church.

     The new educational/fellowship building was added around 1960.