Workers were set to return to their jobs Thursday morning.
The union representing the county workers was not releasing details of the agreement early Wednesday, but representatives said all of the issues that were on the table had been resolved.
About 1,000 members of the American Federation of State, County and Municipal Employees Local 1028 walked off the job Nov. 18 after 15 months of negotiations.
The strike involved more than half of Will County's workers, including those in the health department, nursing home, highway department, sheriff's office, court system and the jail. About 30 had to return to work after federal officials said they were essential and couldn't walk off the job.
(The Associated Press contributed to this report.)