ZIP code 20191, located in Reston, Virginia, has experienced steady population growth over the past decade, with the population increasing from 25,767 in 2010 to 28,899 in 2022. The population density has also risen during this period, from 3,303.46 people per square mile in 2010 to 3,705.0 people per square mile in 2022. Given the ZIP code's size of 7.8 square miles, the 2022 population of 28,899 translates to an estimated 11,072 housing units, based on the national average household size of 2.61.

The population density of 3,705.0 people per square mile in 2022 suggests that the area can be classified as urban. Urban areas are characterized by multi-story residential buildings, commercial buildings, and high levels of infrastructure and services. Living spaces in urban areas typically range from 500 to 1,000 square feet, indicating a more compact and efficient use of space compared to suburban or rural areas.

The lifestyle in urban areas is generally fast-paced, diverse, and culturally rich, making it suitable for individuals and families who enjoy vibrant city life. The high population density and well-developed infrastructure often provide extensive public transportation options, a wide variety of restaurants, theaters, museums, and other cultural amenities.