The group of at least 50 caravans arrived around 4pm, having been moved on by police from Sompting Recreation Ground.
Residents, who say it is the first time they have seen travellers in Middle Road, were quick to complain to East Worthing and Shoreham MP Tim Loughton.
Commenting on the Shorehambysea.com forum, Paul Ockenden said: “That field backs directly onto Kingsland House, which houses 70 very vulnerable residents. Only a very thin and easily breakable fence separating the two.
“Hopefully that will be taken account when deciding when to move the travellers on.”
Other comments on the forum include: “Just driven past, there must be at least 50 caravans on the recreation ground. I’ve never seen so many.
“Apparently they have come from Findon, stopped briefly in Sompting but got moved on straight away. They’ve never been on the rec before.”
Mr Loughton attended the site late yesterday afternoon to talk to the travellers, and received praise on the forum for doing so.
“Just wandered along to the site to have a look. There was Tim Loughton, our much maligned MP with just a female PC in attendance talking to four bare-chested men.
“Full marks to TL for being there without press coverage or any other form of support.”
Chief Inspector Jo Banks, district commander for Adur and Worthing, said: “There was a group of travellers in Sompting who left of their own accord on Thursday afternoon, before we served a section 61 on them.
“We have no influence where they move to next and would not direct them to a particular site.
“We are aware a group of travellers has moved on to land at Middle Road, Shoreham, and we are liaising with the group, residents and the land owners.”