An EIS is a detailed analysis that serves to insure that the policies and goals defined in NEPA are infused into the ongoing programs and actions of the federal agency. EISs are generally prepared for projects that the proposing agency views as having significant prospective environmental impacts. The EIS should provide a discussion of significant environmental impacts and reasonable alternatives (including a No Action alternative) which would avoid or minimize adverse impacts or enhance the quality of the human environment. The standard format for the EIS as outlined in Section 1502.10 of the NEPA Regulations should be followed. Agencies should allow at least a 45-day comment period for draft EISs and a 30-day comment period for final EISs.
(EPA NEPA Home: http://www.epa.gov/reg3esd1/nepa/eis.htm#eis
EIS documents can be prepared by different agencies and they are scatterred. The Transportation Library at Northwestern University holds a large collection of EIS documents. You may try different resources listed depending on your project. (Please contact Lisha for interlibrary loan of an EIS document.)