The church is built on the basilican plan with nave and side aisles. The sanctuary is raised one step from the church floor and separates the nave from the sacristy.
To the right of the church doors is a marble sculpture of the Last Supper. Dating to 1898, the sculpture was originally in the main altar at Sacred Heart Church and was moved here when the former church was deconsecrated and the downtown parishes combined in 1971.
Continuing right are the stairs that led to the bell tower and spire, completed in 1894 with the bell donated by the Dorr family. The bell, weighing 4,750 pounds, is inscribed "Presented to St. Patrick's Church, Augusta, Georgia, 1894, McShane Bell Foundry, Baltimore Maryland, 1894."
Enter through any of the three sets of large panel doors interior of the oldest Catholic Church building in the state of Georgia. On the large arch above the steps features seven circles depicting the seven sacraments of the church. Two lines of columns divide the nave into two side aisles and a center section. The columns divide the length of the nave into six bays. The floor of the last bay at the Sanctuary is raised approximately one foot. Below the ceiling, plaster arches span from the exterior walls to the columns and from column to column lengthwise of the building. The arched panels separating the bays at the ceiling are stenciled with symbols relating to Christ going toward the altar and symbols of the apostles coming back from the altar. The ceiling between the arches is vaulted from the exterior wall to the column line and between column lines across the building. At the Apse, the building projects as a half octagon open to the Nave and having a vaulted ceiling. On the right and left of the sanctuary are the chapels, dedicated to Saints Mary and Joseph, which are connected by large open arches, each contains an altar.
The interior walls are of stuccoed brick masonry completely restored in 1998 to the original light brown color. The floor of the foyer is concrete with a stone surface. The ceiling and arches are made of plaster on wood lath. The altars, three in number are made of Tennessee marble. The floor of the main area are wood with marble tiles at the aisles and the sanctuary.
The interior width is 69 feet and the height is 47 feet from floor to ceiling. Three distinct and transverse arches supported by twelve ornamental iron columns span the ceiling. The ornate columns are painted in gilt and a dark coral, in a diamond-shaped pattern centered with a floral motif. Other painted detailing highlights the arches of the vaults. Of the three frescos, which originally decorated the semi-dome of the sanctuary, only the center one remains. (The side arches of the vault were painted to blend with the center one during the 1998 restoration of the church.)
The principle openings in the church consist of six large stained glass windows on each side, a large one in front above the entrance doors, and three in the rear. Above the front window a rose window, and above the chapel altars are two other rose windows.
The important features of the interior have been retained, with the exception of a large canopied pulpit which was located on the left side of the sanctuary, and the replacement of the simple glass windows with elaborate stained glass ones around 1919. (Also during the 1998 restoration, a new pulpit, chairs, processional candlesticks and cross were commissioned and designed by Images of the Cross to compliment the distinctive architecture of the church.)
Above the organ loft is open to the Nave and a balcony at this level projects into the Nave about eleven feet. The organ loft has a vaulted ceiling matching that of the Nave.
At the beginning of the central aisle is an ornately carved wooden baptismal font topped by a small sculpture of John the Baptist baptizing Jesus. Flanking the center aisle are two marble fonts with holy water.
In the back right corner is a statue of St. Martin de Porris.
The right side aisle windows illustrate events from the life of Jesus. From the back, the first window shows Jesus teaching the children (Matthew 19:13-15); the next window depicts the Ascension of Jesus (Luke 24:50-53); the third window illustrates the devotion to the Sacred Heart of Jesus as seen by St. Mary Margaret Alacoque; the next window shows the young Jesus teaching in the temple (Luke 2:45-50); the final window in the side aisle is Jesus giving Peter the keys to the kingdom (Matthew 16:16-20)
At the top of the right aisle is the chapel of St. Joseph. It contains one of the three altars carved by John Mullen. To the right of the altar is a stained glass window depicting the death of St. Joseph and a statue of St. Patrick chosen primary patron of the church by vote of the clergy and people on Easter Sunday, 1863. The church was popularly known as St. Patrick's Church from 1863 until 1971 when the downtown parishes merged and the consecrated name was retained.
Between St. Joseph's altar and the main altar is a large crucifix donated by a parishioner in 1894.
The main altar and sanctuary are separated from the nave by a marble altar rail with beautiful brass gates. The original wooden altar railing were replaced with marble railing and ornate bronze gates around 1905. Marble tiling was also added to the aisles at this time. Close inspection of the brass gates revels many Christian symbols. The four plaques on the gate display symbols of Christ: a lantern (the Light of the world); carpenter's tools; whips and a sponge with bitter wine (symbols of the Crucifixion); and nails (also from the Crucifixion.) Surrounding these are fish (symbols of the Eucharist), a pelican (symbols of Christ - it feeds its young with its own flesh) and a lamb with a book with seven seals (from the book of Revelation.)
Look pass the gate for a view of the magnificent 19th century altar and the surrounding apse. The apse features three large stained glass windows depicting (from left to right) the resurrected Christ, the Holy Trinity and the Nativity. The apse is crowned by a half dome ceiling, the center portion is an oil painting on canvas, the only original ceiling remaining in the church. At the apex of the dome is a triangle with the symbols of the Holy Trinity.
Look straight up to see the "Christus Rex" (Christ the King) surrounded by symbols of the four gospels: Matthew (cherub), Mark (lion), Luke (bull) and John (eagle). It is flanked on either side by angels.
Turn toward the back of the church for the best view of the historic Jardine tracker pipe organ located in the balcony. The organ is the largest Jardine organ still in existence and the oldest of its size still in use in the South. Because of the Civil War the organ was not installed in the church until 1868, completed restored in 1993, it is still used in services.
The memorial plaques on the walls memorialize five of the faithful priests who served here and are buried under the church. (There are eight priests and one bishop buried in the crypts under the church.)
Continue to the altar of St. Mary which completes the trio of altars. The adjacent stained glass window illustrates the miracles of Bernadette's vision of Mary in Lourdes, France in 1857. Nearby is a statue in honor of the Sacred Heart of Jesus.
As you walk up the left side aisle, the stained glass windows depict the life of Mary: the first shows the Annunciation (Luke 1:26-38); the next Mary visits her cousin Elizabeth (Luke 1:39-45); the third the presentation of Jesus in the temple (Luke 2:21-38); the fourth, the flight into Egypt (Matthew 2:13-15); and the last, the wedding feast at Cana where Jesus performs his first miracle turning water into wine (John 2:1-11.)
In 1963 the current Stations of the Cross replaced original oil paintings in mahogany frames.In the back left corner, outside the confessional, is a statue of St Anthony of Padua.