Interstate 270

Interstate 270 is a major highway spanning roughly 35 miles from Bethesda to Frederick. The road features separate express and local lanes to manage significant traffic volumes.

The road began as an expressway project in the 1950s and received its current designation in 1973. Upgrades occurred gradually to match the region's expanding development.

The corridor passes through an area with numerous biotechnology companies and research facilities. This concentration has shaped the region into a center for scientific innovation.

High-occupancy vehicle lanes operate during peak hours between Bethesda and Gaithersburg for carpools and multiple-passenger vehicles. Understanding the lane configuration helps you navigate more efficiently.

The number of lanes changes dramatically, with twelve lanes in Montgomery County reducing to four lanes in Frederick County. This shift reflects the different population pressures and development patterns of the two counties.

Location: Montgomery County

Location: Frederick County

Inception: 1975

GPS coordinates: 39.01868,-77.10353

Latest update: December 7, 2025 09:24