Ethna Watterson said the cash windfall would go a long way to providing support for those living with the neurological condition which affects walking, talking and writing.
"It is a fantastic amount of money and I was gobsmacked when I found out," Ethna told the Times.
"It will go a long way to helping us carry out our work with the Society.
"Such support is vital to our existence and the money raised will be put to good use throughout the area.
"I can't thank enough those who took part. They were marvellous."
The Causeway Branch was set up almost 20 years ago and UK wide the Parkinson's Disease Society is marking its fourth decade this year.
The branch - which has over 100 members - provides support to those affected by the disease.
This includes respite and recently the branch sent a group to Edinburgh for a break.
Presenting the cheque to Ethna, Michael Allen said:
"First of all I would like to say that I feel the credit for the success of the marathon belongs to the people I am going to mention in my word of thanks.
"To my sister Ruby and niece Rosie for their achievement in completing the gruelling 26 mile run.
"They put in a lot of hard work and training and I want them to know how much I have appreciated their effort and determination.
"Also my daughter Stephanie who printed and designed the sponsorship sheets and registered the relay teams on-line and arranged the transport.
"My niece Nicole who travelled to Belfast to pick up the relay packs and organised the distribution of them.
"Thanks to family members who gave donations and organised marathon fundraising events.
"My heartfelt thanks go to the 26 mile runners Ruby, Rosie and Roger.
"And those in the relay teams: Stephanie, Kyle, Timothy, Ryan B, Nicole, Rachael, Connie, Samuel, Ryan M and Stephen.
"We are so proud of them all. To all the branch who gave and sponsored the teams. Without the support of you all this event would not have been the success it was.
"How can I forget my sister-in-law Wendy who celebrated the big 'five - O' recently and gave £500 proceeds from her party to the Parkinson's Branch.
"We know that this money will be used to make a difference in the lives of Parkinson's sufferers in the Causeway Coast Branch."