Wichita ? A decades-long decline in population is likely to continue in Kansas, particularly in the west of the state, and four counties could have fewer than 1,000 residents by 2040, according to a study by Wichita State University’s Center for Economic Development and Business Research.

Census figures have detailed the decline for years, most recently showing that 77 of Kansas’ 105 counties lost population in the last decade. The population of 41 Kansas counties peaked in 1910 or earlier and 28 counties haven’t recorded a population increase from one census to the next since 1940, not even during the post-World War II baby boom, The Hutchinson News reported.

The center made two separate projections based on different factors. One projection considered birth and death rates and assumed that migration patterns recorded in each county from 2000 to 2010 would continue. The second approach did not factor in migration patterns and considered what would happen as the current population ages.

Historic migration patterns are important but they might not be the best predictor of the future, said Jeremy Hill, director of the center.

“In some of these communities, we’re getting down to a very small population,” Hill said. “People who want to move probably already have left. People who are there are there for one reason or another. They’re attached to the land or they’re there for work and they’ve probably already gone through the agricultural productivity (gains that reduced farm employment). They’re not likely to decline any further.”

Without migration, Wichita State projected that 37 counties — 22 in the western Kansas — would lose population. The main reason for the decline is a relatively low concentration of women of child-bearing age, Hill said.

With migration, the study projected that 83 counties, including 51 of the 54 from Reno County west to the Colorado border, would continue to lose population through 2040. In the western half of the state, only Ford, Ellis and Hamilton counties could be expected to grow.

By either method, Greeley County, which had 1,235 people in the 2010 Census, will be Kansas’ smallest county in 2040. Assuming no migration, Greeley’s population would drop nearly 10 percent to 1,113, according to the study. If migration patterns continue, it would drop nearly 64 percent, to 447 people, and be one of four Kansas counties — along with Wallace, Kiowa and Lane — with fewer than 1,000 people in 2040.

“I don’t necessarily believe that every community will go that low,” Hill said. “At some point we might be at that inflection point where it’s already at the bare minimum of people willing to move out.”

Hill said he believes some communities, even those in rural areas, could grow if U.S. manufacturing rebounds as the costs of doing business in China increase. That would prompt more manufacturing jobs to return to the Midwest because of the relatively low labor costs and the skill set of the work force, he said.

“If we look in Kansas, where?” he said. “Really it’s not going to be Wichita central city, although Wichita will continue to grow. I think there is skill-set value there. However, I think communities around major metros and some other central hubs across the state — Hutch, Hays, Great Bend, Dodge and Pittsburg are great examples — are where manufacturing will likely re-emerge.”