Section 106 of the National Historic Preservation Act (NHPA) instructs federal agencies to consider the effect of any proposed federal undertaking—such as an activity, program, or project—on historic properties. Section 106 review is designed to make federal agencies aware of how their actions might affect historic properties by integrating preservation into project planning in much the same way that the National Environmental Policy Act (NEPA), enacted in 1969, requires federal agencies to consider impacts to the environment. Below are the consultation letters sent to gather information to satisfy this requirement.