Henry B. Clarke House
Clarke House may have been modeled on the home of William B. Ogden. The Clarke house is often described as the oldest surviving house in Chicago, although part of the Noble-Seymour-Crippen House in the Norwood Park neighborhood was built in 1833. (However, Norwood Park was not annexed to Chicago until 1893.) The Clarke House was designated a Chicago Landmark on October 14, 1970. It was added to the National Register of Historic Places on May 6, 1971.
Ludington Building
The Ludington Building is the earliest-surviving, steel-frame building in Chicago, Illinois. It is located in the Chicago Loop community area. It was designed by William Le Baron Jenney and was named a Chicago Landmark on June 10, 1996. It was added to the National Register of Historic Places on May 8, 1980. The Ludington Building "was commissioned by Mary Ludington Barnes for the American Book Company"; presently it is one of twenty buildings that comprise the campus of Columbia College Chicago.