What are the top 10 longest streets in the US?

top 10 longest streets in the US: Route 20 vs Colfax Ave

Exploring the top 10 longest streets in the US reveals major cross-country highways and extensive urban thoroughfares. Understanding these remarkable routes helps travelers appreciate the vast scale of American transportation networks before planning a cross-country road trip.

Understanding What Counts as the Longest Street in the US

The title of the longest street in America depends heavily on whether you mean a local urban or suburban street or a transcontinental federal highway and route. Finding a single definitive answer is tricky because city planners, state transportation departments, and everyday drivers define a street very differently. While federal highways span thousands of miles across multiple states, local urban thoroughfares weave through city blocks and suburbs with distinct regional identities.

Most travelers and researchers divide the conversation into two distinct categories: cross-country federal highways and continuous local urban thoroughfares. Understanding this distinction prevents common confusion between massive national interstate routes and historic city avenues.

Why Definitions Change Everything

Ask a local urban historian what is the longest street in the United States, and they will likely point to continuous city commercial corridors like Colfax Avenue or Western Avenue. Ask a freight truck driver or a cross-country road tripper, and they will immediately reference federal routes like U.S. Route 20 or Interstate 90. Because local street names change frequently at municipal borders, measuring urban continuity becomes a complex puzzle of name shifts and designation overlaps.

Longest Federal Highways and Roads in the United States

If you define streets as major cross-country thoroughfares and federal highways, the scale expands dramatically to thousands of miles traversing multiple state lines. These national routes serve as the economic backbones of the country, connecting rural landscapes with bustling metropolitan centers.

U.S. Route 20 stands as the single longest road in America, stretching approximately 3,365 miles from Boston, Massachusetts, all the way to Newport, Oregon. This massive highway crosses twelve states and even encounters a brief gap through Yellowstone National Park. Not far behind, U.S. Route 6 stretches about 3,207 miles from Provincetown, Massachusetts, to Bishop, California.

Major Interstate Milestones

Among the controlled-access freeway systems, Interstate 90 reigns as the longest highway in the US at approximately 3,021 miles, linking Boston, Massachusetts, to Seattle, Washington. Other notable transcontinental routes include U.S. Route 30 at 3,073 miles and U.S. Route 50, which matches that length while spanning from Ocean City, Maryland, to West Sacramento, California. These monumental routes dwarf any traditional municipal road, though they rarely function as typical city streets.

Famous Local and Continuous Urban Streets

If your definition of a street restricts the term to traditional city-to-suburb commercial avenues and local longest continuous urban streets rather than cross-country highways, the list shifts entirely to regional marvels.

Colfax Avenue is frequently cited as one of the longest continuous commercial and local streets, running roughly 26.5 miles through Aurora, Denver, Lakewood, and Golden, Colorado. Although various historical accounts and measurements vary due to designation gaps, its iconic status remains unmatched in the region.

Suburban Giants and Long Avenues

Other notable contenders include Harlem Avenue, designated as Illinois Route 43, which stretches 54.1 miles from Glenview down to Peotone. Western Avenue in the Chicago area spans roughly 24 to 50 miles total when combining city bounds and extended suburban stretches. Meanwhile, roads like Katella Avenue run approximately 41.7 miles through Orange County, showcasing how suburban expansion transforms local paths into massive regional corridors.

Comparing Major Federal Routes and Urban Streets

Federal Highways (e.g., U.S. Route 20)

- Spans thousands of miles across multiple state lines

- Mix of rural two-lane stretches, expressways, and freeways

- Maintains standardized federal numbering across regions

- Cross-country commercial transport and interstate travel

Urban Commercial Streets (e.g., Colfax Avenue)

- Typically spans 25 to 50 miles through local municipalities

- Characterized by storefronts, traffic lights, and local intersections

- Subject to local name changes and municipal border shifts

- Local commuting, commercial business, and suburban connection

Driving the Length of U.S. Route 20

Mark, an avid road trip enthusiast from Chicago, decided to spend his summer vacation driving the entirety of U.S. Route 20 from Boston to Newport. He anticipated a straightforward coastal-to-coastal journey.

The initial driving days were frustrating due to heavy New England traffic, winding rural two-lane stretches, and unexpected detours near state borders.

Instead of rushing, he adjusted his daily mileage goals and embraced the historic small towns, mountain passes, and changing regional landscapes.

Completing the multi-week trip gave him a profound appreciation for America's longest highway, turning a daunting transit challenge into an unforgettable cultural experience.