Gettysburg National Military Park Expansion Act of 2010 - Requires the inclusion of the Gettysburg Train Station in Gettysburg National Military Park, including land located in close proximity to the Train Station that is in the Borough of Gettysburg, Pennsylvania, and the property that is adjacent to Plum Run in Cumberland Township, Pennsylvania.
Authorizes the Secretary of the Interior to acquire only by purchase from a willing seller publicly owned property that is within the area of the Train Station, if efforts to acquire such property without cost have been exhausted. Prohibits the acquisition by eminent domain of property that is within such area.