What is 301 Area Code?

The 301 area code is one of Maryland’s original area codes, established in 1947. It covers the western and parts of the central region of the state, including cities like Frederick, Rockville, Gaithersburg, and Silver Spring. Today, it serves both residential and business users, with a strong presence in government, healthcare, finance, and technology sectors.

  • State: Maryland
  • Major Cities: Frederick, Rockville, Gaithersburg, Silver Spring, Waldorf
  • Time Zone: Eastern Time Zone
  • Established: 1947
  • Overlay Area Code: 240
  • Region Population: 4.4+ million
  • Primary Uses: Business & residential phone services

Population & Demographics of 301 Area Code

The 301 area code serves a large and diverse population spread across western and southern Maryland, including counties such as Montgomery, Prince George’s, Frederick, Charles, and St. Mary’s. According to the U.S. Census Bureau, this region is home to more than 2.3 million residents, making it one of the most populated area codes in the state. 

The demographic mix includes families, students, working professionals, and retirees, creating a broad customer base for local businesses. Montgomery and Prince George’s counties are among the most diverse in the nation, with significant African American, Hispanic, and Asian communities. This diversity not only shapes the local culture but also drives demand for businesses that can adapt to different customer needs. 

301 Area Code Time Zone

The 301 area code operates in the Eastern Time Zone (ET). This is the same time zone observed in Washington, D.C., Baltimore, New York, and much of the U.S. East Coast. For businesses, this alignment is highly valuable, as it keeps them on the same schedule as major financial, government, and corporate hubs.