Civil War Sites Study Act of 1990

Civil War Sites Study Act of 1990 - Directs the Secretary of the Interior to prepare a study of Shenandoah Valley Civil War sites in Virginia to: (1) identify and determine the relative significance of such sites; (2) assess short- and long-term threats to their integrity; and (3) provide alternatives for the preservation of such sites by Federal, State, and local governments, or other public or private entities. Includes among such alternatives the designation of such sites as units of the National Park System. Requires the Secretary to transmit such study to specified congressional committees.

Establishes the Civil War Sites Advisory Commission to prepare a study of historically significant sites and structures associated with military action during the Civil War, other than Shenandoah Valley Civil War sites. Requires the Commission to transmit such study to the President and the same congressional committees. Terminates such Commission 180 days after transmittal of such report to the Congress.

Authorizes appropriations.