The authority sent the letter to residents in Barthomley about matters relating to the dualling of the A500.
But they failed to put enough postage on the A4 envelopes and residents had to pay Royal Mail the additional £1.50 to receive the letter.
Cllr Steve Edgar (Haslington, Con) said he had received numerous complaints.
“This is ridiculous,” he told the Local Democracy Reporting Service. “Why is an A4 piece of paper in an A4 envelope with inadequate postage? Why couldn’t it just go out in a DL [standard] sized envelope? I’ve had tens of phone calls off residents complaining about having to pay £1.50.”
A Cheshire East Council spokesperson said: “The council is aware of an issue regarding the incorrect amount of postage paid for letters sent out on behalf of the council concerning the proposed plans for the dualling of the A500.
“The council has now addressed this matter, re-issued the letters and assured anyone who has paid the excess postage that they will be reimbursed.
“Around 100 letters were sent to residents, businesses, organisations and other parties who had commented on the planning application for this highway scheme.
“The intended recipients were parties with an indirect interest in the scheme and not those residents or property owners who had already received compulsory purchase notification via courier.
“The council apologises for any inconvenience caused by this unfortunate administrative error.”