San Marcos' surging population appears to be snowballing into even more interest in the city from outside businesses, developers and potential new residents, according to city and development officials.

On May 23 the U.S. Census Bureau announced San Marcos was the fastest-growing city among cities with a population of 50,000 or more in 2012. The population grew by a chart-topping 4.9 percent that year.

Organizations such as the Greater San Marcos Partnership, a group that promotes job creation and economic development in the region, are capitalizing on the marketing potential of the Census Bureau designation. Partnership President Adriana Cruz said her office is incorporating the designation into brochures and presentations when promoting the area to outside companies.

"Being able to use that ranking really surprises a lot of people," Cruz said. "It changes their perception of San Marcos."

Fastest-growing city

San Marcos' relatively small size was a major factor in its ranking as the nation's fastest-growing city, said David Dixon, a demographer in the Census Bureau's population division. The city's population estimate of 50,001 narrowly qualified it for inclusion.

"The biggest thing to consider with San Marcos is that it barely met the threshold for the ranking totals," Dixon said. "When you're comparing the percent increase in an area of 50,000 versus a percent increase in a city of several million, it doesn't take as much numerically for the [high growth rate] in San Marcos."

For example, in 2012 San Marcos added 2,339 people, a number that is dwarfed by the growth experienced by the two largest cities along the I-35 corridor in Central Texas. San Antonio grew by 25,400 new residents, and Austin added 25,395 residents, according to census data.

Because both cities started with much larger population bases, San Antonio's growth rate of 1.9 percent and Austin's growth rate of 3.1 percent appear less dramatic than San Marcos' 4.9 percent rate, Dixon said.

By comparison, the Census Bureau estimated the city of Kyle grew by 5.4 percent—to 30,875 people—and Buda grew by 8.2 percent to 9,381 people in 2012.

Estimating population change

Dixon said the Census Bureau uses local and federal administrative records to determine its population estimates. First the bureau's demographers add up the population of an entire county using data from the IRS and Medicare, as well as immigration and birth records. The bureau also takes into account that three counties are included in San Marcos' city limits.

In addition, demographers calculate housing data for each city within the county based on existing homes, new construction and demolition, among other factors. Then they compare the population growth to the housing growth and distribute the population estimates to each city based on its number of homes.

"There were some questions about the student population [in San Marcos], but it's difficult to determine because we're not seeing population growth in group quarters such as dorms," Dixon said. "We're seeing it in housing units, which could be inhabited by a student or not."

Dixon said questions about San Marcos' population following the 2010 census had "nothing to do" with its rate of growth in 2012.

2010 census surprise

San Marcos officials were taken by surprise when results of the 2010 census indicated the city was much smaller than previously thought.

In 2008 the Census Bureau certified that San Marcos' population exceeded 50,000, a trigger that carries a number of implications such as access to state and federal funding, expanded jurisdiction beyond city limits and a seat on the Capital Area Metropolitan Planning Organization board, among other benefits.

Although the Census Bureau had estimated the city's population at 53,205 in 2009, the decennial census indicated San Marcos had a population of less than 45,000. City officials believed San Marcos residents were undercounted by census workers.

"You can attribute that to a number of variables, whether it was lower response, poor turnout, or whatever it might be," San Marcos Mayor Daniel Guerrero said.

City officials worried that San Marcos might lose out on some of the benefits of having more than 50,000 residents. Those concerns turned out to be unfounded, Guerrero said, because the city population of more than 50,000 had already been certified by the Census Bureau.

Sustained growth

San Marcos' population increase shows no signs of slowing, San Marcos Planning Manager John Foreman said.

Apartment complexes opening this summer and fall will provide about 2,500 new bedrooms, encouraging Texas State University students to stay in town rather than commute from Austin, and permits for single-family home construction continue to come in, he added.

"We see it on the ground that people are moving here," Foreman said. "In the next month or two, the numbers are going to go up pretty quickly based on new housing."

While San Marcos prepares for continued population increases, Guerrero said city leaders are committed to maintaining the city's character and heritage while enhancing residents' quality of life through infrastructure projects and other improvements.

"We're just pleased that folks are seeing San Marcos as a great place to grow their families and build their businesses and really set down roots," Guerrero said.