St. Andrew’s Parish was created by the Maryland Provincial Assembly in 1744 from parts of two adjoining parishes, All Faith Parish on the north, and William and Mary Parish on the south. The northern boundary was from Breton Bay and Major Barnes’s Mill on Breton Bay Run to Cole’s Creek on the Patuxent. The southern boundary was from Legrande’s Creek on the Patuxent to Poplar Hill Creek on the Potomac.

The new parish could not be organized until the rectors of All Faith and William and Mary resigned or died, thus releasing their freeholds. After the rector of William and Mary, the Reverend Lawrence De Butts, died in 1752, the parishioners in the northern part of William and Mary that was to be included in St. Andrew’s Parish elected vestrymen and wardens in 1753 and started functioning as a parish. 

On November 27, 1753, William Russell made the first entry in the “Register for St. Andrew’s Parish” now in the Hall of Records in Annapolis. Worship services were held in the courthouse in Leonardtown. The Reverend Moses Tabbs of William and Mary parish served as rector of St. Andrew’s also until 1757 when he assigned curates to serve St. Andrew’s Parish.  In 1764, the Reverend John Urquahart of All Faith Parish died, releasing the northern part of St. Andrew’s Parish.

Within this part of St. Andrew’s Parish was the Four Mile Run Church, which had been a Chapel of Ease of All Faith Parish, located near what is now Sandy Bottom, on the Three Notch Road. The Four Mile Run Church was used by St. Andrew’s Parish until St. Andrew’s Church was built. Four Mile Run Church and its graveyard, where Governor Plater’s mother and father were buried, have now disappeared. 

In April 1766, two acres of land, called Waldrums’ Old Field, were purchased from Samuel Bellwood for five pounds currency as a site for the new church. It should be noted that this property fronted the now abandoned road that was perpendicular to the existing paved road. This abandoned road is still the boundary between the third and eighth election districts of St. Mary’s County.

One reason the new parish of St. Andrew’s had been established was to serve Leonardtown, which had become Maryland’s first incorporated town and the county seat of St. Mary’s County in 1710.  Just why the new church of this parish was built five miles from the town in an isolated spot is not clear.  However, the site was near the geographical center of the new parish.

On April 17, 1766, the vestry decided to build a church 70 feet long and 40 feet wide according to Richard Boulton’s plan, for which he was paid five pounds currency. However, nine days later, the vestrymen changed their minds about the size of the church, and the following specifications were recorded in the register: 

“The church to be 55 ft. long in the clear exclusive of chancel and 40 ft. wide in the clear; to be painted inside and outside, pews to be wainscoted and painted; pillars to be fluted and capped; a handsome pulpit and reading desk; pews to have doors; aisles to be laid with flag stones; a handsome altar piece of lonic order. Two galleries to be wainscoted; portico with pyramids; roof to be planked with cypress shingles. Outside quoins to be built with stock bricks as also all the outside of the walls. One arched ceiling and two flat ceilings. Ground glass with chemical party. Foundation of wall to be 3 ½ bricks thick; from the water table to the eaves 2 ½ bricks thick. Height of walls 14 t. from floor to flat ceiling. Outside and inside work and pews to be painted over three times with white lead; folding doors, weights for the sashes. To be finished by Richard Boulton’s plan (the middle spire excepted): the portico to be laid with brick edgeways”

Little is known of the architect of the church, Richard Boulton. He was an indentured servant to Colonel George Plate of Sotterley, an important parishioner of St. Andrew’s. Boulton is also credited with the construction of the unfinished Chinese Chippendale staircase in Sotterley Mansion. The only other building known to have been constructed by Boulton is All Faith Church near Charlotte Hall. This church was built after St. Andrew’s and is similar in design, although considerably smaller.  St. Andrew’s Church was entered in the National Register of Historic Places on March 14, 1973. 

 St. Andrew’s is considered to be among the most unusual of Maryland colonial churches by virtue of its twin west towers embellished by brick quoin, the inset portico, the two convex tapering columns, the palladian or venetian window, the fluted lonic interior columns the two-level gallery, and the reredos.  

The reredos is the most unique feature of the church, and was painted in 1771, when the vestry supplied one “John Friech, Limer” with the lampblack, white vitriol, and a book of gold leaf to finish the altarpiece. He was paid 16 pounds, 10 shillings currency, and his board and materials. It took him five weeks to complete this magnificent work. When it was completed, the vestry hired Thomas Thompson for seven shillings and six pence to “glue the big board”. The “board” is surround by magnificent carving, forming the “handsome altar piece” called for in Richard Boulton’s plan. This reredos remains as originally painted, although it has been treated for preservation. The arrangement of the three fundamentals of the faith, the Lord’s Prayer, the Creed, and the Ten Commandments, combined into one unit as a reredos is unique among Maryland colonial churches. 

Meanwhile, the vestry had commissioned the Reverend Mr. West and John Black, a vestryman, to purchase various church linens. As far back as 1757, Col. Barnes had been asked to send for a surplice, two church prayer books, a church Bible, one silver chalice and salver. Regrettably, all that is known to remain of these original purchases is the church Bible, which is still in excellent condition. The age and origin of old communion silver in possession of the parish has not been definitely established, except for one chalice, which is dated 1869.