Congratulations to beans&franks for FTF.
HGA stands for Holy Guardian Angel Church, although it is mostly known just as Guardian Angel Church. It was the first Roman Catholic church in the area. The church is no longer used except on Christmas Eve, but you can peek in the windows if you care to glimpse the interior. The attached old cemetery (or should I say graveyard!) has some really interesting headstones in it also.
Up until after the American Revolution in 1776, Pennsylvania law prohibited Catholic churches from being built, although they did allow meeting houses (such as the Quakers had) or Catholic Chapels. About 1800, Casper W. Easley, Sr received this land for his service in the American Revolution and he settled here from Maryland. He was the initiator of the church but it wasn't until 1872 that there was a priest in the area and there was a need for a church building. In 1872, right before his death, Casper W. Easley, Jr donated part of his farmland for the church and accompanying cemetery.
Construction was started in 1872 and that year is written above the front door of the church in the tower and in the keystone along with the words "HOLY GUARDIAN ANGEL", but the building wasn't formally dedicated until 1878. It is known that the outside was finished fairly quickly and that the congregation met in the unfinished building for several years until the interior was finished in 1878. Most likely, the inside was finished as money became available. The brick building is 32' x 57' and is built in the Gothic Style. There are no exact records, but it is thought that the bricks were hand fired on the site as the church was being built. When done, the church had 3 alters and seated 200, and according to old records most of those seats were usually filled. A 32' high bell tower was added on in 1908, but after a bad storm in the late 1900s it was greatly reduced in height.