Online collections are able to extend the multiple important functions of museums to many individuals beyond the confines of museum walls. Thus, this paper examines the availability of, and ease of access to, art museum collections presented online via institutional web sites. Focusing on art museum collections in the United States, this project analyzes the data behind the representation of museum objects in the online setting to codify and report on shared descriptive and multimedia practices. Furthermore, it highlights common difficulties (e.g., determining the sort order of retrieved items, and the meaning of field labels) visitors experience while examining online collections. This presentation seeks to clarify the current state of the art surrounding online art museum collections and provide context for why studies of visitors to museum web sites report limited use of online collections. Questions concerning the fundamental features of online collection access, such as what percentage of collections are available online and the semantic commonalities found across museums, are explored and allow us to reflect upon how far museums have extended their reach.