Map showing the 20 cities projected to have the fastest growth rate (2020-2025) in the USA. America?檚 fastest growing city is The Woodlands, Texas (4.76% projected growth). Several factors affect city growth including ease of transportation, housing supply and weather. Agglomeration is also a factor whereby an entrepreneurial city, which attracts new firms and helps foster growth for existing firms, allows for natural population increase. Data from UN World Urbanization Prospects 2018.