property, structure or object which adds to the historical integrity or architectural qualities that make a historic district, listed locally or federally, significant. Different entities, usually governmental, at both the state and national level in the United States, have differing definitions of contributing property but they all retain the same basic characteristics. In general, contributing properties are integral parts of the historic context and character of a historic district. In addition to the two types of classification within historic districts, properties listed on the National Register of Historic Places are classified into five broad categories. They are, building, structure, site, district and object; each one has a specific definition in relation to the National Register. All but the eponymous district category are also applied to historic districts listed on the National Register. Federal-level A listing on the National Register of Historic Places is governmental acknowledgment of a historic district. However, the Register is "an honorary status with some federal financial incentives." The National Register of Historic Places defines a historic district per U.S. federal law, last revised in 2004. According to the Register definition a historic district is: a geographically definable area, urban or rural, possessing a significant concentration, linkage, or continuity of sites, buildings, structures, or objects united by past events or aesthetically by plan or physical development. A district may also comprise individual elements separated geographically but linked by association or history. Districts established under U.S. federal guidelines generally begin the process of designation through a nomination to the National Register of Historic Places. The National Register is the official recognition by the U.S. government of cultural resources worthy of preservation. While designation through the National Register does offer a district or property some protections, it is only in cases where the threatening action involves the federal government. If the federal government is not involved, then the listing on the National Register provides the site, property or district no protections. For example, if company A wants to tear down the hypothetical Smith House and company A is under contract with the state government of Illinois, then the federal designation would offer no protections. If, however, company A was under federal contract the Smith House would be protected. A federal designation is little more than recognition by the government that the resource is worthy of preservation. In general, the criteria for acceptance to the National Register are applied consistently,