An air ambulance helicopter was seen landing close to the aqueduct at about 4pm on Monday.
Four ambulances, four police cars and a number of fire engines were also reportedly on the scene near the B5070, with Shropshire Fire and Rescue Service saying it had two crews helping in the rescue of one person.
Police were reportedly parked by the Bridge Inn on the A5 which overlooks the aqueduct.
The circumstances of the emergency are not yet apparent, however Superintendent Jon Bowcott said: "Officers from North Wales Police, along with colleagues from emergency services from both Wales and England this afternoon responded to a medical emergency in the vicinity of Chirk Aqueduct.
"The activity in the area has understandably created significant public interest and concern.
"Operations at the site have now wound down, and I would like to reassure people that there was never a threat to the wider public nor are there any ongoing issues of concern."
A spokesperson for Shropshire Fire and Rescue Service said: "SFRS Fire Control received a call reporting an incident classified as SSC Urgent in Wrexham.
"Two fire appliances including the Water Rescue Unit were mobilised from Oswestry and Shrewsbury. An Operations officer was in attendance.
"Crews assisted Ambulance crews in rescue of one person. Over the border appliances from Llangollen and Deeside also attended."