Each year, during the fall equinox, Chicago experiences a unique event known as “Chicagohenge.” This occurs when the sun rises and sets perfectly down the city’s east-west streets, such as Kinzie and Madison. This alignment creates a stunning visual effect reminiscent of the solar alignments seen at Stonehenge.
This phenomenon is tied to the shorter days and seasonal changes brought by the fall equinox. It also offers a chance to see the sun’s alignment with city streets, similar to ancient celestial observations. Geoff Boeing, an expert in city design at the University of Southern California, notes that such alignments reflect how humans frame the universe with the structures they build.
Michelle Nichols from the Adler Planetarium in Chicago explains that in the city’s downtown area, tall buildings accentuate the Chicagohenge effect. The city’s streets, designed along cardinal compass points, contribute to this striking alignment with the sun.
The fall equinox in the U.S. in 2026 arrives on September 22. This marks the beginning of autumn in the Northern Hemisphere and spring in the Southern Hemisphere. Other grid-like cities, such as Washington, D.C. and Phoenix, can also witness similar sun alignments.
The Role of Urban Planning
Boeing shares that aligning cities with celestial points is a concept dating back thousands of years. For early civilizations, such as the Aztecs with Tenochtitlan, city planning included astronomical elements to align with stars and celestial changes.
In modern cities, this cosmic alignment often happens by chance due to grid layouts. Although intentional design isn’t always the case, the visual impact remains significant.
Spotting Henge Alignments in Your City
Cities like Chicago and Denver are ideal for equinox observations due to the consistent adherence to compass-aligned grids, Boeing notes. He points out that the grid system facilitated land sales and infrastructure development during the U.S. westward expansion in the 19th century. Other cities, despite not aligning with the compass, may still offer unique views.
For instance, New York’s “Manhattanhenge” and San Francisco’s “California Henge” are notable, though they don’t coincide with the equinox dates. Observers should remain vigilant, as irregular street alignments can still provide interesting sights.
Capturing the Moment Safely
The equinox has gained popularity on platforms like Instagram for capturing dramatic scenes, says Nichols. During pandemic lockdowns, it offered a way to experience a shared event while apart. However, safety is paramount. Nichols advises taking photos from the sidewalk instead of the street to avoid accidents.
Driving on east-west streets during these times can pose a challenge due to glaring sunlight, which may obscure visibility. Nichols cautions that traffic backups are common under such conditions.
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