The remains of Garda Michael Padden were removed from his aunt's home near Belmullet, Co Mayo, last evening to Shanaghy Church on the Mullet peninsula.
The parish priest of Kilmore Erris, Father Kevin Hegarty, received the remains at the Church of Our Lady of Dolours and led prayers for the popular 27-year-old, who grew up in the area.
Such was the turnout that the tiny chapel - which was built in the early 1960s and has a capacity of less than 200 people - could not accommodate the huge throng of mourners.
The Belmullet-based curate, Father Michael Nallen, who joined Father Kevin Hegarty in prayers at the home of the dead garda's aunt, Ms Angela Padden, at Tallagh, Belmullet, on Monday night, recalled Michael Padden yesterday as courteous and friendly.
He said that although he had bought a house in Dublin, Michael hoped eventually to get a transfer within the ranks of the Garda Síochána and move back to his native west of Ireland.
Garda Padden's mother, Marian, attended last night's removal. Her husband, Michael John, who worked in the construction business for a period after spending some time in the force, died some years ago.
Chairs were being brought from Belmullet to Shanaghy last night so that elderly mourners who cannot get a seat in the church for today's funeral Mass can sit outside and listen to the ceremony on speakers.
The recently ordained Bishop of Killala, Dr John Fleming, will preside at today's Mass.
Father Hegarty will be the main celebrant.
The Garda Deputy Commissioner, Mr Noel Conroy, a native of the Erris area, is expected to be among the mourners today.
Due to the fact that Shanaghy Church is on the main approach road to Ballyglass Pier, where Ballyglass Lifeboat is based, a special appeal has been made by the Lifeboat Secretary, Supt Tony McNamara, for the public not to park along the route during today's funeral.
A newly developed football pitch, some 400 metres from the church, was used as a carpark during last night's removal and will fulfil a similar role today when even larger crowds are expected.
A number of other special car-parking areas have been designated and gardaí will be on duty to direct motorists into these off-road locations.
Following midday Mass at Shanaghy Church, the remains of Garda Padden will be brought to Emlybeg cemetery some five miles away.