Warren Howard Hayes (1847–1899) was a leading designer of churches in the United States and Canada during the late 19th century. Hayes' work holds a significant place in its association with the "Social Gospel" movement. He is credited with some of the earliest use of the "diagonal auditorium" plan and the vast majority of his churches uncovered to date are centered on the diagonal auditorium design with fan shaped pew arrangements and, to assure excellent acoustics, the seating sloping toward the pulpit and domed ceilings. As noted at the opening of the Rockville Ct. Congregational Church:

The acoustic properties of the auditorium are something wonderful. The pastor says he never before spoke in church or hall which can compare with it in this respect. There are yet to be added a protected desk light for the pulpit and a shaded reflector for the organ. The seating capacity of the auditorium is 600, of the gallery 300, of the chapel 300. This capacity can be extended by placing chairs in vacant spaces without obstructing any aisles from 100 to 200 more. —Warren H. Hayes of Minneapolis.

Often the interiors have Arts and Crafts movement attributes, and some of the congregations accepted Hayes recommendations of Louis Tiffany for their stained glass.

From early in his career Hayes worked closely with artists-decorators, such as Lawrence A. McIvor, who worked for Hayes in Elmira, and later followed him to Minneapolis where he worked as the L.A. McIvor & Company. While attentive to the look and sounds of his churches, Hayes also was an early adopter of advanced mechanical and electrical systems.

The National Register of Historic Places currently includes seven of his works in Minnesota and the Methodist Episcopal Church at Lodi, New York.

Hayes was deeply involved in the institutional church movement throughout his career, and although he was a Methodist, he had extensive ties with other denominations. This is well illustrated in the nationwide dissemination by various church organizations charged with promoting church building and development of his ideas and plans in the late 19th century.

The National Cyclopaedia of American Biography included a lengthy entry about Hayes, together with some family background, five years before his death:

On his father's side he is of New England stock, being descended from George Hayes, of Windsor, Connecticut, who emigrated from Scotland to Derbyshire, England, and thence to Windsor, Connecticut, in 1680, where descendants of the family still live. Many honored names represent the family in professional and official life, 19th President of the United States Rutherford Hayes being among the number. Upon his mother's" side, Mr. Hayes' progenitors are the Robsons and Straughans, of Northumberland, England, who emigrated to Geneva in Ontario, early in the nineteenth century. The boyhood of Mr. Hayes was spent on the farm of his father, George Goundry Hayes, who was at that time one of the most successful agriculturists in that section, owning and tilling large farms in Yates, Steuben, and Ontario. The son's studies were begun at the age of five in the district school, and continued for seven years. This was supplemented at the select school in Italy, New York, at Watkins' Academy, and at Genesee Wesleyan Seminary at Lima, New York.