The bulk of the collection consists of Henning's projects, which were primarily schools, churches, government buildings, libraries, hospital and businesses in Anderson, Indiana, and surrounding Madison County. Some of his largest projects were City Hall, Community Hospital, Fire Department Headquarters, and Anderson High School, all in Anderson, Indiana. Other projects include multiple buildings on the Anderson College campus, Central Christian Church, First Methodist Church, and numerous schools in the area. Items in the collection include photographs, building dedication booklets, newspaper clippings, articles, and reference books.
One of his most outstanding projects is the threatened Anderson High School gymnasium, the second-largest high school gymnasium in the country. After the community of Anderson consolidated its two remaining high schools in recent years, the former Anderson High School and gymnasium were left vacant. The Wigwam, as it is known, has been a vital part of the community since its construction and dedicated preservationists are currently looking for new uses for the building. Above is a two-page spread from the building's dedication booklet, when the future burned bright for this gymnasium.