Lincoln Home National Historic Site Boundary Modification Act This bill modifies the boundary of the Lincoln Home National Historic Site in Illinois as generally depicted on the map titled Proposed Boundary Expansion of the Lincoln Home National Historic Site and dated February 26, 2021. To improve accessibility, the Department of the Interior shall modify the following areas located within the boundary of the historic site to provide universal design and accessibility by raising the height of the street to match the height of the sidewalk with no sloped surfaces: the intersection at 8th Street and Jackson Street, and the area in front of the home of Abraham Lincoln.