The trick or treaters will be out in force this weekend for Halloween, which means many churches will be celebrating All Hallows and All Souls Day.

But one of the oldest churches in Brisbane will be celebrating the lives of some of the city's earliest settlers who are still buried under major infrastructure of the inner-northern suburbs.

For nearly 170 years, thousands of bodies have been lying under parts of inner-city Brisbane.

In 1843, Brisbane was a small but rapidly expanding port and farming city.

Dirt roads and thick bushland surrounded the city's then fringe suburbs of Milton and Paddington.

As the city expanded, it was not just the living that needed somewhere to rest.

Hundreds of people were dying and there was no room to bury them.

Gailene Harrison from the Christ Church Historic Society, says a five-acre site was chosen to the north of the city, as the final resting place of the early pioneers.

"Lots of mothers died giving birth and lots of little children died," she said.

First public cemetery

Between 1843 to 1875, as many as 2,000 bodies were buried in Brisbane's first public cemetery on the border of what is now the suburbs of Milton and Paddington.

The cemetery soon filled up and in the 1850s fell into disrepair.

Wild goats were running rampant and drunks used to frequent the then dark and dirty part of Brisbane.

The old Moreton Bay Courier newspaper began reporting on nearby residents falling ill as heavy downpours sent dirty run-off from the cemetery, into the Milton reservoir.

"People died because of infections, they caught terrible infections from the putrid water and mosquitos," Ms Harrison said.

"They just had a very poor hygiene."

The only visible remnant left today is the small wooden church and adjoining memorial garden next to Lang Park stadium.

Ms Harrison says the church was built on the old Anglican mortuary in the middle of the cemetery.

"Which doesn't sound very charming, but apparently they fitted about 50 or 60 people in it and then they saw the need to build another church for Christ Church parish," she said.

Toowong cemetery

In 1866, the council began clearing trees at a new 260-acre site at Toowong.

Ms Harrison says families were encouraged to exhume their ancestors, before redevelopments began in the Milton area.

"The bodies are still there but the cemetery's long gone of course," she said.

"In its place, the councillor at its time saw fit to build sport fields.

"So all of those areas are really changed now into places of joy."

Today Lang Park Stadium, a council pool, childcare centre and scores of homes sit on top of the burial grounds.

Remembrance celebration

Ann Fiddler, also from the Christ Church Historic Society, says every year her community stops to remember these somewhat forgotten souls of early Brisbane.

"All Souls Day is in the church calendar and every year we celebrate all souls that have passed away and that are no longer with us," Ms Renal-Fiddler said.

"It's a celebration of their life and what they meant to the community and to each and every person."

She says out of the thousands of tombstones from Brisbane's earliest cemetery, only a dozen now serve as a memorial at the church site.

"I did have a couple of people call me, they were looking for a great-great grandmother," she said.

"Another gentleman was looking for a great-great uncle and I had to say unfortunately, they're not the names that we've got unless they've been moved to Toowong.

"Unfortunately a lot of the tombstones were crushed and used for road fill and taken away.

"If they're not there or if that didn't happen to them, they are unfortunately under Suncorp Stadium."

Gruesome murder

Only a few dozen bodies were exhumed from the old Milton Cemetery and taken to the spacious resting grounds at Toowong.

One of these who made the move, caused quite a stir in his living years.

Patrick Mayne was known by locals as a wealthy rogue, who used to horse whip people he did not get along with.

Brisbane historian Rosamond Siemon says Mr Mayne was responsible for one of Brisbane's most gruesome murders in 1848 at the old Bush Inn at Kangaroo Point.

"One night, the people had been drinking until closing time which was quite late at the hotel, and parts of the body were found next morning, lying either side of that spit of Kangaroo Point," she said.

"The legs were on one side and the torso and arms on the other.

"The head was eventually found propped up on a building that was being constructed and the entrails were found put down a well in the hotel, where they kept their milk, butter and cheese down under the hotel."

She says another man was hung for the murder and several years later Patrick Mayne confessed to the deed on his deathbed.

"The person who was called in for this was the cook form the hotel," Ms Siemon said.

'He clearly didn't do it, he wouldn't have been so mad as to put all the entrails of a corpse he'd murdered all over the food he had to eat.

"Apart from that he had a good alibi from the publican and his daughter."

But Mr Mayne met his fate at the age of 44 after a severe mental condition left him in and out of hospital.

'Parks for people'

After they died, the Mayne family were some of the ones who were removed from Milton before the 'parks for people' program redeveloped the old cemetery in the early 1900s.

"There was one problem with the Milton Cemetery, a very big problem; when it rained it flooded and a lot of the corpses used to float," Ms Siemon said.

"One of the fellows told me, his grandfather used to say every time it was raining, 'I think Paddy [Patrick Mayne] will float again today'.

"Whether he did or not, we'll never know."