Large numbers of people are to be prevented from gathering on Pont y Pentre at Llanfairfechan in Conwy.
The order was put in place after complaints of people drinking alcohol on the bridge late at night.
The deputy mayor of Llanfairfechan said youths had mostly been sitting on the bridge watching the world go by, but the sheer numbers collecting there was getting too much.
The notice will operate from 0600 BST on 9 August until 9 February next year.
"There is no-where for youths aged from 16 to 18 years old to go, and this bridge near the chip shop is an ideal place to sit and watch the comings and goings," said deputy mayor Gareth Jones.
"Older people were feeling intimidated by them however.
"Also because you have to cross the bridge no matter where you are going in Llanfairfechan you'd maybe start with a group of six or seven, but then others would come along and stop to chat, and quite quickly the numbers would be quite large," he added.
Mr Jones said nearby residents had also complained about late-night noise on the bridge.
"When I was growing up here there was nothing to do from the age of 14 to 16, and it's the same today, only worse now because there's no money either.
"We are trying very hard to get something for them however, and one idea is to open a cafe - maybe with a games room - so they would have somewhere they could go in the evening," he added.