In November of 1833 Barton Randle preached the first Methodist sermon in Dubuque and the following June a log church was built on the present site of Washington Park. Many class me​etings were formed quickly as non-indian settlers moved into the area.​

Among those settlers influenced by John Wesley, was a group from Swaledale Valley in Yorkshire, England who arrived in 1834. Its class meeting was first led by Richard Waller and by 1835 a new congregation was formed. The articles of incorporation were signed in 1836 and the members first used a log schoolhouse located just north of the present church of worship in 1838. A formal church was built between 1843 and 1846. The church took the its name from the native town of its members in England, which was Rockdale.

The church gave birth to two daughter churches when Center Grove was formed in 1852 and Reed's Chapel in 1867.

 The present sanctuary was constructed in 1874, with the bell tower added in 1913 and a kitchen and Fellowship Hall in 1960. From 1990 to 1992, the fellowship hall was renovated and an electric organ was added to the sanctuary. Recent modifications to the entry have made the church completely handicapped accessible. In 2014, the sanctuary was updated again with newly surfaced walls, paint and new carpet and a new steel roof was installed. In 2015 the new brick and steel sign in the front was donated by several members. In 2018, the kitchen was renovated with updated cabinets, flooring and counter space. The small congregation continues to support the improvements to keep the beautiful 180+ year old church operating and sharing the love of God.

The engraved stone that is in front of the sidewalk leading into church was originally the step into the church before the new handicap accessible walkway was installed. The members had Rockdale United Methodist Church carved into the stone and lights continue to shine on the stone because the 

Rockdale United Methodist Church is strong as a rock.