(NEXSTAR) — Americans on the move are largely heading to the South and West, especially to areas in Texas and Arizona, new data from the Census Bureau has found. Yet while many cities and towns were growing, some of the nation’s largest were suffering population losses.

Between the summers of 2020 and 2021, Census data found cities in these regions — eight in the West, seven in the South — had the greatest rate of population growth. Seeing the largest increase was Georgetown, Texas, with a rate of 10.5%. Located about 30 miles north of Austin, Georgetown’s population could double in less than seven years if its growth continues at the same rate, researchers found.

Roughly 12 miles west of Georgetown is Leander, the country’s second-fastest-growing city. A third Texas city, New Braunfels, which is between Austin and San Antonio, also landed in the top five fastest-growing.

Five Arizona cities ranked in the top 15 fastest-growing, while Idaho, Texas, and Florida each had three.

Here are the 15 fastest-growing cities in the U.S.:

When comparing the total number of people moving in, the Census Bureau found cities in the South and West also had the greatest increase. Again, a Texas city topped the list: San Antonio, with an increase of 13,626 people. Close behind was Phoenix at 13,224.

Seven cities had both high rates of growth and numeric growth: Port St. Lucie, Buckeye, New Braunfels, Georgetown, Meridian, Leander, and Fort Myers.

These 15 cities welcomed the most new residents between 2020 and 2021:

Among the nation’s most populous cities, more than half saw their population decrease between 2020 and 2021: New York, Los Angeles, Chicago, Houston, Philadelphia, San Diego, Dallas, San Jose and Indianapolis.

New York City, which suffered the greatest population decrease at 305,465, still held onto its title as the nation’s most populous city. The Big Apple edged out Los Angeles and Chicago, with the rankings throughout the list remaining the same as they were in 2020.

Here are the U.S.’s 15 most populous cities:

Seven U.S. cities surpassed a major milestone in 2021 and recorded a population of 50,000 or more. Among those are three from Texas — Kyle, Burleson, and Little Elm. Also in that select group are the Indiana cities of Westfield and Jefferson, as well as Lincoln, California, and Newark, Ohio. Another six cities saw their populations surpass 100,000 in 2021. Among those are Bend, Oregon; Fishers and Carmel in Indiana; and three in Arizona — Tuscaloosa, Goodyear, and Buckeye.

The majority of cities and towns in the U.S. have a population under 5,000, according to Census data, yet they are home to less than 1% of Americans. Cities with a population of 50,000 and more — of which there are less than 800 — hold more than 60% of the country’s people.

Reasons for population changes vary from city to city, driven by housing costs, jobs, births and deaths. The pandemic and the lockdown that followed in spring 2020 made living in a crowded city less appealing for a time, and those who could leave — workers who could do their jobs remotely, for example — sometimes did.

The Associated Press contributed to this report.