The Keith Estate is significant under Criterion A in the area of settlement as an example of the type of estates wealthy northerners established in the Sarasota area during the boom period of the early 20th century. It is significant under Criterion C in the area of late 19th and 20th century revivals as an outstanding example of Italian Renaissance architecture in the local area, designed by the prominent Chicago architectural firm of Otis and Clark. The property is also significant under Criterion D as a prehistoric archaeological site that is likely to provide important data on the little known Manasota culture (500 BC to 800 AD) of the central Florida Gulf coast. - NRHP, 14th March 1991