To amend the National Trails System Act to update the feasibility and suitability studies of 4 national historic trails and provide for possible additions to such trails.

Amends the National Trails System Act to direct the Secretary of the Interior to undertake a study to determine the feasibility of designating: (1) certain routes and cutoffs for inclusion within the Oregon National Historic Trail; (2) the southern alternative route from Wathena to Troy, Kansas, for inclusion within the Pony Express National Historic Trail; (3) certain Missouri Valley central and western routes and cutoffs for inclusion within the California National Historic Trail; (4) certain routes and cutoffs for inclusion within the Mormon Pioneer National Historic Trail; and (5) certain routes and cutoffs as shared components of the California and Oregon National Historic Trails. Requires the Secretary, as appropriate, to so designate such routes and cutoffs, to publish notice of such designation, and to submit study results to specified congressional committees.