FORT LEAVENWORTH, Kan. — The economic engine that drives St. Joseph can be likened to a patchwork quilt, and one piece people don’t often think about is Fort Leavenworth.

“The Army spends $1.2 billion a year on salaries, supplies and services at Fort Leavenworth,” said Jack Walker, deputy to the garrison commander. “Money goes across the bridge to a lot of communities within a 50-mile radius of the fort.”

One is St. Joseph. Currently, the Army has more than 20 civilian employees who live in St. Joseph and drive back and forth. Those employees earn $1.4 million in salaries each year, said Jeff Wingo, an Army spokesman at the military base.

The 20 include Robert Horton II, who develops computer scenarios for the Army. Mr. Horton graduated from Missouri Western State University in 2001 with degrees in mathematics and computer science.

“I got my job at the fort thanks to Kent Pickett, an assistant professor of computer science at Missouri Western,” Mr. Horton said. “A lot of Missouri Western graduates are here because of that man.”

Scott Cox also earned a Missouri Western degree in computer science. The spring before he finished college, he went to a job fair on campus.

“I knew I had a job at Fort Leavenworth before I graduated,” he said.

Computers were what led Anthony Carriger to Fort Leavenworth. After leaving the Missouri Air National Guard’s 139th Airlift Wing, he eventually wound up in Nebraska, where he started a computer technical assistance business.

“In October 2008, I got a contract at the fort, and this August that translated into a civilian job,” Mr. Carriger said. He plans to stay in St. Joseph to be near family.

Another longtime employee, John Adair, started out as a firefighter in 1989. Now, Mr. Adair is the fort’s fire chief, managing 40 employees.

All four men spend a lot of time and a good portion of their salaries in St. Joseph.

Mr. Adair raises horses. “And I spend thousands of dollars every year at Upco Pharmaceutical Supply and the TSC (Tractor Supply Company) store,” he said.

Mr. Horton has sponsored foreign students from Mali, Canada and Bahrain that come to study at the Army’s Command and General Staff College. He said he looks for activities in and around St. Joseph that the students might enjoy. Last year, he brought a student up to Hunt’s Apple Orchard to see the pumpkin patch and the foods the orchard has for sale.

Mr. Cox is a collector, so his weekends and part of his paycheck are often spent at estate sales and antique malls.

It isn’t always economics that keeps these Army civilians in St. Joseph. Some just like the city.

Christopher Schmelze, a computer and information specialist, grew up in Atchison but found work for several years in St. Joseph and liked the community. So after he got a job at Leavenworth, he didn’t see any need to move. He enjoys St. Joseph’s hiking and biking trails.

“The really nice thing is that, thanks to the city, those trails keep growing,” Mr. Schmelze said.

Mr. Horton likes the small-town feel of St. Joseph. “St. Joseph has that ‘Cheers’ type of thing — where everybody knows your name,” he said.

The Army impact reaches out to other area communities. Records indicate that more than 50 civilian employees live in Atchison, Kan., and bring home salaries totaling $3.1 million. Weston, Mo., has about 30 employees who earn $1.5 million. But the big winner is Platte City, with more than 100 employees who bring $7 million in salaries to the growing community.

“It’s axiomatic to me that St. Joseph is going to continue to be impacted by the fort,” Mr. Walker said. The Northeast Leavenworth Development Plan is working to make this area the “Silicon Valley of the Midwest,” he said.

Mr. Walker said he believes the future will see continued growth. The fort is preparing to add another military police battalion, and that means about 300 people. “If they don’t have advanced criminal justice degrees, they will be looking for a school,” Mr. Walker said.

The Command and General Staff College is slated to increase the number of students attending each year. Those students are often looking for another school to pursue advanced degrees, Mr. Walker said. It also means the college will be looking for more professors, he added.

For any community located within 50 miles of the Army fort, there could be increased economic impact.

“If I were a university president or the mayor of a nearby town, I think I’d be in touch with Fort Leavenworth,” Mr. Walker said.

Marshall White can be reached at marshall@npgco.com.