The mess left behind by a student beach festival made Pembrey Country Park look like a "bombsite", according to the local mayor.
Police have praised the behaviour of the 12,500 people at Beach Break Live, which was held over four days last week. Fourteen arrests were made.
Burry Port and Pembrey mayor Stephen James said the event had been well policed but it was not the right venue.
Organisers want the park with its beach to be the festival's permanent home.
Officers said the vast majority of the students camping at Pembrey had been in good spirits and were well behaved. Fourteen arrests were made.
Carmarthenshire council also said noise levels from the park were well within agreed limits.
Town councillor Mr James admitted many of the inital concerns the community had had about the "negative impact" of a large festival had not materialised.
He said the students he had spoken to were largely "very polite", adding: "It was a joy to see them there".
However, he said, overall, he and many other local people, still believed the country park was not a suitable place for the festival, which is aimed exclusively at students.
He added that he and members of the town council were "shocked" at the amount of litter left behind, and described the park as looking like a "bombsite".
"We would hold that's not the right venue - it's a country park, family orientated. Thousands of people use that park on any given weekend, particularly when the weather is good," he said.
"They have been prevented from using the park [as it was closed during the festival]."
He said he believed those living closest to the park had suffered most.
"The town council, which has led the campaign here on behalf of local residents, put very strongly to the police and to the county council their concerns and it's because of that we have had perhaps the vigorous controls that we have seen within the event," he said.
"But there has been some negative impact particularly for those residents living close to the park - the noise, the traffic issues."
Before the festival, headlined by Vampire Weekend and Calvin Harris, concerns were raised by some residents in Burry Port and Pembrey about potential trouble.
But Ch Insp Mark Bleasdale of Dyfed-Powys Police said he had been impressed with the behaviour of most of those camping in the country park. The arrets made included those for drug offences, theft and public order offences.
Carmarthenshire council's executive board member for leisure, Clive Scourfield, who visited the festival, added: "I think there are probably more problems in Llanelli on a Saturday night than there are at this festival. "