The country's largest metro system is the New York City Subway which has a system length of 337 kilometers / 209 miles. The country's oldest metro system is the city of Chicago's L Train which began operation in 1892.

Yes, the United States has several extensive "metro" or rapid transit systems, though their prevalence varies by region. The most famous and largest is the New York City Subway, which operates 24/7 and covers the most stations of any system in the world. Other major "heavy rail" metro systems include the Chicago "L" (the country's oldest), the Washington Metro (WMATA), Boston's MBTA (The "T"), and Philadelphia's SEPTA. In California, the Bay Area Rapid Transit (BART) serves San Francisco, while the Los Angeles Metro has seen massive expansions leading into 2026. Additionally, many cities utilize "Light Rail" systems, such as Seattle's Link, Portland's MAX, and Denver's RTD. While the Northeast corridor is the most densely connected by rail, cities in the South and West—like Atlanta (MARTA) and Miami (Metrorail)—also maintain significant rapid transit networks. However, outside of these major urban cores, public transportation in the U.S. is often more reliant on bus networks and commuter rail.