The McMillan Plan was an architectural plan for the city of Washington that was created at the beginning of the 20th century to improve upon the original city plan that was designed in 1791 by Pierre L'Enfant. Senator James McMillan of Michigan chaired a committee of renowned architects, landscape designers, and artists (known as the McMillan Commission) to expand L’Enfant’s desire to surround public buildings with landscaped parks and open spaces. The plan removed many of the slums that surrounded the Capitol and created the National Mall.
The McMillan Plan was developed by visionary architect Daniel Burnham, landscape architect Frederick Law Olmsted, Jr., architect Charles F. McKim, and sculptor Augustus St. Gaudens. The plan called for re-landscaping the Capitol Grounds, selecting a site for a monument to Abraham Lincoln, adding new extensions west and south of the Washington Monument, relocating the city railway (building Union Station), designing a coordinated municipal office complex in the triangle formed by Pennsylvanian Avenue, 15th Street, and the National Mall (Federal Triangle), and establishing a comprehensive recreation and park system that would create national pride in the capital city. In addition to the McMillan Commission, Congress established a Commission of Fine Arts as a consulting organization to the government on the design of bridges, parks, paintings, and other artistic matters.
The National Park Service has posted the full 261 page McMillan Plan online on their history website.