The decision comes after months of consultation and has been met with both desperation and delight.
More than 2,300 comments were received from residents and organisations on 18 different sites proposed last year.
Now, after analysing the results, a total of 15 permanent pitches, demanded by the Government to meet the needs of gipsies and travellers, will be situated at Cottage Garden in Beads Hall Lane, Pilgrims Hatch; Willow Park in Stock Lane, Ingatestone; Roman Triangle in Mountnessing; Hope Farm in Horsemanside and Goatswood Lane in Navestock; and Treetops in Curtis Mill Lane, Navestock.
It means dozens of families living in illegally-built homes already on the sites can stay without the threat of eviction.
Brentwood Borough Council says the decision was made reluctantly.
Council leader Cllr Brandon Lewis said: "Whether we agree personally or not, it is in the best interest of the borough to accept 15 additional authorised permanent residential pitches be provided by 2011, as instructed by central Government.
"In doing so, it is preferable to consider the existing sites with temporary permission or existing unauthorised sites to avoid creating even more sites than we already have.
"Purely on balance this seems to be the best thing to do in a bad situation."
Prof Thomas Acton, secretary of the Brentwood Gypsy Support Group, said: "We are delighted. We are very pleased and grateful that the council has shown some courage in doing the best and recognising what has to be done."
He added: "You can't legislate people away. The only way to stop illegal sites is provide somewhere for them to go."