A six-bedroom, 9,815-square-foot mansion in Elmhurst sold June 1 for $4.2 million, setting what easily is a record for the highest-priced home sale in that DuPage County suburb’s history.

A four-bedroom Mediterranean-style mansion in Elmhurst that is a prominent local landmark sold on Sept. 26 for $2.39 million — more than 36% less than the sellers had sought for the home when ...