Mayo Clinic is in the early stages of planning a new campus in Onalaska, Wis., where about 3,800 people eventually could work.

Officials with the Rochester-based health system did not respond to messages seeking comment about the plans.

Joe Chilsen, the mayor of Onalaska, said he didn’t have much information about Mayo’s development proposal, which was the subject of a traffic study being presented Tuesday to the city’s Board of Public Works.

“The Mayo Clinic is proposing to construct a new campus in Onalaska, WI, located on the east side of Sand Lake Road,” the report states. “The proposed clinic will be constructed in phases that could ultimately accommodate 3,800 employees at full development.”

Onalaska is just north of La Crosse, where Chilsen said the city’s hospital is operated by Mayo Clinic. Mayo already operates a clinic in Onalaska, but the new development would be “multiples bigger than the existing clinic,” he said.

“We’re very, very early in the process,” Chilsen said in an interview. “They will be the biggest employer in town.”

County records show that Mayo Clinic purchased property along Sand Lake Road in early 2014 for about $8.3 million — a price that also was reported Tuesday in a story about the plans by the Associated Press. The traffic study is scheduled to go before the City Council next week.

Mayo Clinic operates a network of hospitals and clinics that spans six states — Arizona, Florida, Georgia, Iowa, Minnesota and Wisconsin. Last year, the nonprofit health ­system had 59,497 employees.