This branch of the Farquhar family is not part of my direct line but I found this info in a book and wanted to share it.

From Immigration of the Irish Quakers into Pennsylvania – 1682-1750 by Albert Cook Myers, M.L. from the Genealogical Publishing Co. Inc., 1902, Swarthmore, PA, pages 398 and 399.

The Farquhar Family

Allen Farquhar, who was not a Friend, came from Ireland, and in 1725 and 1726 was a resident taxable in Chester County, Pa., as of New Garden Township. After this he removed to Pipe Creek, now Carrol County, Md. His son William, b. in Ireland 7 Mo. 29, 1705, d. at Pipe Creek 9 Mo. 21, 1778, remained in Chester County for some time, and became a member of New Garden Mo. Mtg., where he married, 2 Mo. 19, 1733, Ann Miller, daughter of James and Katharine (Lightfoot) Miller, also from Ireland (see pages 356-7). In 1735 they removed to Pipe Creek, taking a certificate of removal to Hopewell Mo. Mtg., in Virginia, and settled near where the town of Union Bridge, Carrol County, Md., now stands, on land conveyed to him by his father, with the provision that he was to move from “ye province of Pennsylvania to ye province of Maryland,” and occupy the same.

William Farquhar was influential in establishing the Friends’ Meeting at Pipe Creek, the meetings for the first few years being held at his house. Children of William and Ann Farquhar: James, b. 1733; William, b. 10 Mo. 11, 1735, m. (1) Rachel Wright and (2) Mary Baily; Allen, b. 10 Mo. 16, 1737, m. Phebe Hibberd; Mary, b. 11 Mo. 22, 1739, m. Joseph Wright; George, b. 6 Mo. 9, 1742; Samuel b. 5 Mo. 8, 1745, m. Phebe Yarnall; Elizabeth, b. 6 Mo. 13, 1748, m. Joel Wright; Moses, b. 11 Mo. 3, 1750; Susanna, b. 9 Mo. 1753, m. Solomon Shepherd.

Allen Farquhar, another son of Allen the emigrant, died 12 Mo. 12, 1800 in his 81st year, and Sarah his wife 7 Mo. 4, 1829, in her 97th year. They had seven children: Thomas, b. 11 Mo. 16, 1751, m. Hannah Edundson; Sarah, b. 11 Mo. 13, 1753; William, b. 12 Mo. 24, 1755; Rachel, b. 2 Mo. 7, 1764; Robert, b. 7, Mo. 13, 1766; Mary, b. 11 Mo. 6, 1769; Samuel, b. 9 Mo. 21, 1772. — Cope, Genealogy of the Sharpless Family, 202-3.

I don’t have any further info on this guy, sorry.
Here is my photocopy from the book:
Allen Farquhar From Ireland
(I don’t remember where I found this book.)