Great Island Presbyterian Church is the oldest church in Lock Haven, Pennsylvania, and was named after the "great" island in the Susquehanna River near Lock Haven. It has existed as an organized church since 1792, when a log church was erected as a "meeting place" on Bellefonte Avenue, west of High Street. This original church building was also used as a school. On April 9, 1794, the first pastor, the Reverend Isaac Grier, was ordained and installed. Rapid missionary expansion resulted from Reverend Grier’s pastorate, and the territorial responsibility accepted by Great Island Church expanded.
The congregation worshipped in several buildings through the years. Between 1845 and 1850, worship was held in the upper room of the Academy at the corner of Main and Vesper Streets. In 1855 a new church was constructed on East Water Street near the canal, facing the river (that building is currently in use as the Jaycee Building). In 1872 the Gothic revival style church at 12 West Water Street was completed at the cost of approximately $42,000. With minor changes, this church is still in use today.
The first ordination of a son of Great Island Church was for Philip Wolcott Furst on July 12, 1935 by official action of the Presbytery. He was a descendant of William Dunn, an early, local settler and one of the first elders. The second ordination took place on January 27, 1957 for Alexander Ungvary, a Hungarian refugee, who had been a member of the church. The third ordination, on July 24, 1988, was held when Christopher Todd Looker, the son of the Reverend and Mrs. Russell L. Looker, was ordained as a minister of the word and sacraments.