With the nearest Catholic Church 16 miles away in Milford, Most Rev. John J. Monaghan, third Bishop of Wilmington (1897-1925), felt that it was time to build a church to meet the needs of the increasing Catholic population in the Lewes / Rehoboth Beach area. In 1905, the Diocese of Wilmington purchased property in Rehoboth Beach for the site of a Catholic Church. All the property, which ran the full length of the oceanfront block between Laurel Street and Brooklyn Avenue, was originally owned by the Rehoboth Beach Camp Meeting Association of the Methodist Episcopal Church. The Diocese established a rectory and a chapel on the property. Two large cottages were also built for the Sisters of St. Francis, teaching and nursing order in the diocese, as a summer vacation retreat.
The small chapel was unable to accommodate all the Catholic worshipers who began swelling the Rehoboth Beach community in the summer. So, a new frame church, overlooking the ocean, was built. The church was named in honor of St. Agnes, the patron saint of the first Mother Superior of the Order of Saint Francis of Assisi. Bishop Monaghan celebrated the first Mass there on July 7, 1906. The following is an excerpt from an article that appeared in the Wilmington Morning News on June 18, 1906, regarding the opening of the new Church:
The new Roman Catholic Church at Rehoboth, the first in Sussex County, is rapidly nearing completion and the first services will be held in it about the first of July. The new edifice, while not a pretentious one, is fitted to the needs of a summer resort which, heretofore, has been but scantily patronized by Catholics because there was not place for them to worship. A few years later, Bishop Monaghan established a temporary church at the resort, but the needs became so pressing that it was decided to erect a building to be devoted to the purpose alone.
The church when dedicated will be known by St. Agnes-by-the-Sea. The seating will be about 200 persons and the parish will be in the charge of the Reverend Father Felix Hintermeyer, O.S.B., of St. Mary's College, Belmont, NC. The building is located on a plot of ground adjoining the summer home of the Sisters of Saint Francis and will be used by them as a chapel.
Although it was reported that Father Felix Hintermeyer was called to the ministry in Rehoboth, the records of the Chancery Office of the Diocese of Wilmington do not support this appointment.
St. Agnes-by-the-Sea was a mission to St. John the Apostle Church in Milford. Services were predominantly celebrated during the summer months; Sunday services during the winter depended upon the availability of a priest.
The early history of St. Agnes-by-the-Sea was influenced considerably by severe storms that battered Delaware's Atlantic Coast. After receiving some damage after a Nor'easter on December 7, 1914, the church was moved farther back from the beach and turned so that its front faced the beach and ocean. After another severe storm in April of 1918, the church was again moved further back from the oceanfront. During the Great Storm of March 1962, the old church suffered irreparable damage and was razed shortly thereafter.