Boston
232 km²
Philadelphia
370 km²
USA
United States
Area Comparison
Boston is 1.6x smaller than Philadelphia
Population Comparison
Boston has 2.4x fewer people than Philadelphia
Philadelphia is significantly larger, covering 1.6 times the area of Boston. Philadelphia spans 370 km² (143 mi²) while Boston covers 232 km² (90 mi²) — a difference of 138 km².
To put Boston's size in perspective, its area of 232 km² is roughly the same size as Amsterdam. Meanwhile, Philadelphia at 370 km² is about 1.6x smaller than Seoul.
Boston's footprint is roughly about 32,000 American football fields, 110 times the area of Monaco, or 68 times the area of Central Park — pick whichever unit feels intuitive. Philadelphia, by comparison, equals about 52,000 American football fields, 180 times the area of Monaco, or 110 times the area of Central Park.
Boston is the capital and most populous city of the U.S. state of Massachusetts. It serves as a cultural and financial center of New England, a region of the Northeastern United States. Boston has an area of 48.4 sq mi (125 km2) and a population of 675,647 as of the 2020 census, making it the third-most populous city in the Northeastern United States after New York City and Philadelphia.
Known as "Beantown", Boston covers 232 km² with a population of 0.7 million. The city was established in 1630. Boston is known for Fenway Park, Freedom Trail, Harvard University, among other attractions. The city's main transit system is the MBTA (The T).
Boston covers just 125 km2 yet serves as the cultural and financial heart of all New England
Philadelphia, colloquially referred to as Philly, is the most populous city in the U.S. state of Pennsylvania, and the sixth-most populous city in the United States, with a Census-estimated population of 1,574,281 in July 2025. The Philadelphia metropolitan area has 6.33 million residents and is the nation's ninth-largest metropolitan area. Philadelphia is known for its culture, cuisine, and history, maintaining contemporary influence in business and technology, sports, and music.
Also known as "Philly", Philadelphia has an area of 370 km² and is home to 1.6 million people. The city dates back to 1682. Visitors come for Liberty Bell, Independence Hall, Philly Cheesesteak, and much more.
Philadelphia is the sixth-most populous US city, with an estimated 1,574,281 residents as of July 2025.
Boston has a population density of 2,931 people per km² — a moderately dense city. Philadelphia, with 4,324 people per km², is a moderately dense city. Both cities have comparable density, though Philadelphia is slightly more compact.
Density Gap
Philadelphia is 1.5x more densely populated
Boston covers 232 km². Cities with a similar urban footprint include Osaka (225 km²), Kuala Lumpur (243 km²), Amsterdam (219 km²), Helsinki (214 km²), or Edinburgh (259 km²).
Philadelphia covers 370 km². Cities with a similar urban footprint include Seattle (369 km²), Dhaka (368 km²), Portland (376 km²), Atlanta (348 km²), or Denver (401 km²).
The straight-line distance from Boston to Philadelphia is 436 km (271 miles), with an estimated flight time of ~1h 1m.
Want to explore more? Compare city sizes for any two cities worldwide, or share your location live with friends.