It is best viewed from the Ellipse, a large open field behind the White House, or from Lafayette Park in front of the building. A limited number of tickets for free tours are available from the White House Visitor Center at 1450 Pennsylvania Avenue on Tuesdays through Saturdays all year round. The Tours start from a grandstand on the Ellipse. The Washington Monument is the most prominent feature of the DC skyline. It is best viewed from the steps of the Lincoln Memorial at the western end of the Mall where an inverted image appears in the large reflecting pool.
Tickets are available at a kiosk near the base of the monument.
The elevator ride costs only 50 cents. Go to the kiosk early in the morning to obtain tickets for use later in the day, or go to the monument late in the evening when the wait is not so long. The Smithsonian Institution, composed of 14 separate facilities scattered about Washington DC, is one of the finest collections of museums in the world. Nine of the museums are located on The Mall between the Capitol Building and the Washington Monument. This great photo-map of the mall is on the official Smithsonian site.