The South Building, with the Jamie L. Whitten Building to the north. Image from Google Maps.

We first published this article on August 28, 2014. We’re sharing it again since the history is still interesting.

The Department of Agriculture South Building an archetypal federal building: Big, beige, and boxy. But it’s missing a corner. Why? The L’Enfant Plan and a street that no longer exists.

The South Building‘s façade stands about 30 feet back from Independence Avenue. The south entrance to the Smithsonian metro stop fits so cozily into the corner, it almost looks as if the notch was built just for it. Of course, that doesn’t square with the history.

This building was an exercise in making efficient use of the land. Unlike Federal Triangle, or Southwest’s modernist buildings, its walls run right up to the property line. With long, thin wings connected at the perimeter, the South Building was as efficient as an office building could be before air conditioning.

When completed in 1936, it was the largest office building in the world. Only the Pentagon would unseat it. On Independence Avenue, its facade runs for 900 feet of beige brick and green-painted steel.

The architect, Louis Simon, wouldn’t have built the setback if he didn’t have to. Looking at an aerial photo provides no clues. But, if you look at an older satellite photo, the reason becomes obvious.

The South Building in its context in 2012. The missing corner is on the left side of the image.

The South Building in its context in 1941.

Pierre L’Enfant’s Virginia Avenue slightly clips the block. You can’t see it now, because urban renewal replaced that section of Virginia Avenue with bas-relief urbanism and highway ramps. Ironically, the sightline the architects so carefully avoided was erased 30 years later.

And this brings up the last reason it’s so mysterious: The architects went out of their way to hide the difference between the corners. Rather than clipping it diagonally along the property line, Simon’s team designed an orthogonal setback that seemed like it was the natural place for the wall.

With two pedestrian bridges and a long walk in between each corner, it’s really hard to notice the difference. I wouldn’t have noticed it had it not come up in the dispute over the Eisenhower Memorial’s setbacks.

For now, it’s another one of DC’s carefully hidden quirks, like the off-axis position of the Washington Monument, or the Jefferson Memorial sitting slightly to the south where Maryland Avenue would be. As Southwest is rebuilt, and Virginia Avenue returns, the purpose of the notch will become more clear.