The decision to refuse planning for a mast in Rossmore Park has been appealed.
Cignal Infrastrure had been seeking permission for the development, and has now brought it to An Bord Pleanala.
The application was submitted after the area surrounding the Monaghan town park was identified as a coverage blackspot.
However, a number of submissions were made in opposition to the 39 metre tall mobile and broadband tower.
The Council ruled that the mast would have a negative impact on the park and surrounding properties.
The applicant has said there is technical justification for having the development, and also submitted visual impact assessments and appraisals to support its appeal.
A decision on the application is due next March.