Current population estimates for the city put the number at around six-hundred and thirty thousand people--making it the 24th largest city in the United States.
What is the current population of the greater Washington DC metro area?
The DC Metropolitan region is a much larger area that includes between 17 and 22 counties--depending on the counting method used--the surround the city. The US Census Bureau estimates that the population of the area is upwards of almost six million people--most of whom live in Northern Virginia but also Maryland and to a lesser extent in West Virginia.
What about the number of people who live in the DC-Baltimore Metro Area?
The Greater Baltimore-Washington region (Baltimore is less than 40 miles to the Northeast) is used as a measure by some government agencies and includes over 9 million people. Roughly, four million people live in suburbs around DC, and more than a million people live in exurbs (regions farther out).
Workday vs. Non-Workday
Though the city has a residential population of around 600 thousands, the city's daytime population reaches to over 1 million during the workweek. Many who work in Washington commute from surrounding areas of Virginia, Maryland, and West Virginia--some coming from as far away as cities such as Richmond or Baltimore.
Has its population ever been greater?
Yes. The number of people residing in the District of Columbia was actually larger between 1940 and 1980. Factors affecting many major cities in country such as suburbification and city crime rates led many residents to leave the DC during the 1980s and 1990s. At around the start of the new century, the population of Washington increased with the rise in government jobs, better standards of urban living, and shorter commutes. Though, many have criticized that DC's population trends have made housing in the district less affordable for low-income residents as wealthier professionals return to the city.