You’ve probably seen it. If you’ve ever walked from the Smithsonian Castle toward the waterfront in D.C., you’ve definitely run into it. It’s that massive, concrete-heavy structure that looks like it’s hovering over 10th Street.
Most people call it an eyesore. Some call it a masterpiece of Brutalism. Officially, it’s the James V. Forrestal Building, and honestly, it’s one of the most polarizing slabs of architecture in the United States.
It’s the headquarters of the Department of Energy (DOE). But before it was the "Energy Building," it had a much more aggressive nickname: the Little Pentagon.
Why the James V. Forrestal Building is basically a concrete bridge
The first thing you notice about the Forrestal Building isn't the windows or the doors. It's the fact that you can walk right under it.
The building is literally suspended over L'Enfant Plaza. This wasn't just a design quirk; it was a solution to a massive urban planning headache in the 1960s. The architects—Curtis and Davis, along with Fordyce and Hamby—had to figure out how to put nearly 2 million square feet of office space in a spot that was supposed to be a scenic vista connecting the National Mall to the Potomac River.
Their answer? Build a bridge.
The North Building, which is the part that spans 10th Street, sits on massive concrete pilotis (basically giant stilts). This was supposed to keep the "view" open. In reality, it created a dark, somewhat cave-like tunnel that D.C. locals have been complaining about since 1969.
- Size: Roughly 1.7 million square feet.
- Composition: Three main structures (East, North, and West) connected underground.
- Style: Brutalist. That means lots of "béton brut" (raw concrete).
The man behind the name: Who was James V. Forrestal?
It's kinda weird to name a Department of Energy building after a guy who was the first Secretary of Defense. James V. Forrestal never actually worked in the energy sector.
He was a Wall Street powerhouse who became the Secretary of the Navy during World War II. He was a workaholic. People called him "pugnacious." He oversaw the Navy’s massive expansion into the greatest fleet the world had ever seen.
The building was originally built for the Department of Defense. When it was completed in 1969, thousands of Army personnel moved in. It was only in 1977, when President Jimmy Carter created the Department of Energy during the energy crisis, that the building changed hands.
The name stuck.
The "Ugly" Debate: Is it actually that bad?
If you ask the Commission of Fine Arts, the answer is a resounding "yes."
Back in 2005, the Commission actually called the building a "barrier to good urban design." They basically said the building acts like a giant wall that cuts off the city from its own waterfront.
But there’s a flip side.
Architectural nerds and Brutalism fans love it. They point to the repetitive, deep-set windows that create these incredible shadows at sunrise. They love the coffered ceilings under the overhang. It feels permanent. It feels stable.
In a city of white marble and Greco-Roman columns, the James V. Forrestal Building is a middle finger to tradition. It represents a 1960s vision of the future that was all about efficiency, raw power, and "the dignity of the federal government."
What’s happening inside those concrete walls?
Today, the building is the nerve center for America's energy policy. We're talking nuclear security, the national labs, and the push for renewable tech.
Because it’s a high-security government facility, you can’t just wander in for a tour. The security modifications over the last twenty years—bollards, fences, guarded checkpoints—have only made it feel more like a fortress.
Interesting side note: despite its rugged exterior, the building has been undergoing a "green" makeover. In the mid-2010s, they swapped out over 30,000 light fixtures for LEDs, which reportedly saved the taxpayers hundreds of thousands of dollars a year. It’s a bit ironic—a Brutalist behemoth trying to become a model of energy efficiency.
Surprising facts you won't find on the plaque:
- The Basement is huge. There are two levels of office space entirely underground that connect the three buildings. It’s like a subterranean city.
- It nearly didn't happen. There were massive debates about whether a building this big should be allowed to block the 10th Street corridor.
- The "Little Pentagon" label. It earned this because it consolidated so many military offices that were scattered across D.C. during the Vietnam War era.
The Future of the Forrestal Building: Will it be torn down?
As of 2025 and 2026, the building's future is actually up in the air.
The Public Buildings Reform Board has recommended the site for "disposal." That’s government-speak for "we might sell it."
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The logic is simple: the building is old, expensive to maintain, and sits on some of the most valuable real estate in the world. Developers are salivating at the thought of tearing it down to create a mixed-use "gateway" between the Mall and The Wharf.
Mayor Muriel Bowser’s 2026 budget even includes funds for a master plan for this area. If the DOE eventually moves to a more modern, efficient headquarters, the Forrestal Building might finally meet the wrecking ball.
Actionable insights for your visit
If you’re a tourist or a local looking to see the building before it potentially disappears, here’s how to do it right:
- Go at Golden Hour: The concrete looks best when the sun is low. It turns from a dull grey to a warm, sandy gold.
- The Best Angle: Stand on the north side near the Smithsonian Castle and look south. You'll see exactly how the building "swallows" the street.
- Walking Path: Walk from L'Enfant Plaza through the "tunnel" under the building. It’s the best way to feel the sheer scale of the 10th Street span.
- Respect the Rules: This is a high-security federal building. Don’t try to take photos of security checkpoints or guards. Stick to the architecture.
The James V. Forrestal Building isn't just a place where people work on energy policy. It’s a relic of a time when the U.S. government wanted to project absolute strength through heavy concrete. Whether you love the style or hate the "bunker," you can't deny that it’s one of the most significant landmarks in Southwest D.C.
Next Steps: Check the National Capital Planning Commission (NCPC) website for the latest updates on the Southwest Ecodistrict Plan. This will tell you if the demolition or redevelopment of the Forrestal site has moved from "proposal" to "scheduled." If you're a fan of mid-century architecture, get your photos now—the Little Pentagon might not be around for another fifty years.