<P> This list of tallest buildings in Washington, D.C. ranks high - rises in the U.S. capital city of Washington, D.C. The tallest structure in the city, excluding radio towers, is the Washington Monument, which rises 555 feet (169 m) and was completed in 1884 . The structure, however, is not generally considered a high - rise building as it does not have successive floors that can be occupied . The tallest habitable building in the city is the Basilica of the National Shrine of the Immaculate Conception, which rises 329 feet (100 m). The second - tallest building in Washington is the Old Post Office Building, which is 315 feet (96 m) high . The third - tallest building in the city is the Washington National Cathedral, which rises 301 feet (92 m) above grade . The cathedral is built on high ground known as Mount St. Alban, 400 feet (120 m) above sea level, which makes the central tower the "highest" point in the District . As of November 2011, there are 410 completed high - rises in the city . </P> <P> Washington's history of skyscrapers began with the completion in 1894 of the 14 - story Cairo Hotel, which is considered to be the city's first high - rise . The building rises 164 feet (50 m) and 14 floors . Washington went through an early high - rise construction boom from the late 1890s to the mid-1930s, during which time the Old Post Office Building and the Federal Triangle were built . The city then experienced a major building boom from the early 1940s to the late 1990s, during which the city saw the completion of 31 of its 48 tallest buildings, including One Franklin Square and 700 Eleventh Street . However, although the city is home to several high - rises, none are considered to be genuine "skyscrapers"; only two completed buildings surpass 200 feet (61 m). </P>

What's the tallest building in washington dc
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