Is Tokyo’s Imperial Palace Really Bigger Than the City of London? (The Royal Run)

Last updated: May 19, 2026

A Green Giant in the Concrete Jungle

Tokyo is globally famous for being an incredibly dense, neon-lit concrete jungle. But right in the absolute center of this bustling metropolis is a massive, tranquil void of deep green forests and ancient water moats. This is the Tokyo Imperial Palace (Kokyo), the primary residence of the Emperor of Japan. To understand just how massive this royal real estate is, consider this: the palace grounds cover about 3.4 square kilometers (1.3 square miles). That means this single private residence in the middle of Tokyo is actually significantly larger than the entire “City of London” financial district!

The Most Expensive Land on Earth

The history and value of this land are mind-blowing. Built on the former site of Edo Castle, the grounds are surrounded by massive stone walls that date back to the samurai era. Because of its sheer size and prime location, the property’s value is astronomical. During the absolute peak of the Japanese economic “Bubble” in the late 1980s, real estate prices skyrocketed so wildly that it was famously estimated that the land beneath the Imperial Palace was worth more than all the real estate in the entire state of California combined!

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The “Kokyo Run” Phenomenon

Today, while you cannot just wander into the Emperor’s backyard, the outer perimeter has become the stage for a massive modern phenomenon: the “Kokyo Run” (Imperial Palace Run). The path around the moat is exactly 5 kilometers (about 3.1 miles) long, making it the perfect running track. Every evening after work, thousands of Tokyo office workers change into their sneakers and run this loop. It has zero traffic lights, beautiful views of the city skyline blending with ancient castles, and high police security, making it the safest and most popular running route in the entire country!