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Gaithersburg, 
United States
274,439 people lived in Gaithersburg in 2025. It is the 2116th largest of the world's 12,138 cities, and the 70th largest in the United States.
The UN measures every city in the world the same way, by where the buildings are rather than where the boundary runs, so this figure and Gaithersburg's own can differ widely. What counts as a city here.
Verified 2026-09-30 · 73 canaries
People · every five years · 1975 to 2050
How Gaithersburg grew
For every 10 people in Gaithersburg in 1990, there were 49.3 in 2025.
On the UN's projection it will have 318,599 people in 2050. It passed 250,000 people between 2015 and 2020. The UN first counts it as a city in 1990, when it passed 50,000 people.
projected (after 2025) · how sure the UN is: high moderate low
How to read this: read it left to right, 1975 to 2050, one column every five years, the height being people. Hatching marks the projected years. Below, a strip of the UN's confidence: strong colour where the census maps are recent and detailed, pale where they are not, blank where the place was not counted as a city.
People · your family's years · 1975 to 2050
Gaithersburg through your family’s years
Put in the years your family were born. You’ll see how many people lived in Gaithersburg in each of those years, and when each of them turned 30.
United States · every city · 2025
Where it is
How to read this: every dot is one of the 348 cities in the United States in 2025, and a dot's area is how many people live there, the biggest being New York City. The ringed dot in colour is Gaithersburg; the grey dots are the rest. The outlines around them are neighbouring countries.
Area and built-up land · km²
How much land it covers
In 2025, Gaithersburg covered 120 km², and buildings, roads and other built-up land covered 20 km² of it. That is 71 m² of built-up land for each person, about a square 8 by 8 metres. Since 1990, its built-up land has grown to 6.8 times its size, and its people are 4.9 times as many.
How to read this: each pale square is the city's whole area, the strong square inside it the part that is built on; one scale for all three, so a bigger square is more land. Hatched is the UN's projection.
Of every 100 people in the United States
Its share of the United States
Of every 1,000 people in the United States in 2025, 1 lived in Gaithersburg, which is 274,439 people.
How to read this: 1,000 squares stand for everyone in the United States, one square for every 1,000th person. Count the coloured ones and you have Gaithersburg's share; the grey remainder live somewhere else in the country.
Ranked by people · 2025
Cities of a similar size
In the world, 2025
- 2111 Pucallpa Peru274,639
- 2112 Reading United Kingdom274,632
- 2113 San Salvador de Jujuy Argentina274,625
- 2115 RICCO Industrial Area India274,572
- 2116 Gaithersburg274,439
- 2117 Xianning China274,146
- 2118 Abu Kabir Egypt274,073
- 2120 Vehari Pakistan273,823
- 2121 Magboro Nigeria273,818
In the United States, 2025
- 1998 Euclid290,669
- 2011 Tacoma289,128
- 2049 Poway283,508
- 2076 Copperfield279,805
- 2116 Gaithersburg274,439
- 2176 Bellevue267,696
- 2238 The Woodlands260,732
- 2247 Hazel Dell259,716
- 2257 New Orleans258,413
How to read this: names are in order of size, the leading number being each city's rank among all 12,138 in 2025; the bars share a scale within a list. A jump in the ranks means a city under 300,000 people, which is not given a page here.
Apparatus
Sources and method
The figures for Gaithersburg are the UN's own, at five-year steps: an estimate for each of 1990 to 2025, then projection to 2050. Projected years are drawn hatched, and the UN publishes no range of uncertainty for a city. What a city means here, how the UN measures one, and why that number can differ from the one Gaithersburg publishes about itself: how the figures here are put together.
Sources: UN WUP 2025 · Natural Earth · flag-icons. Every source, its licence and how to cite it →
Verified 2026-09-30 · 73 canaries