On 3 May 1780 when Abraham Pierson was 26, he married Abigail Allen, daughter of Gilbert Allen, in First Presbyterian Church, Morristown. Abigail died in Romulus, Seneca County, New York aft 8 Jun 1818.

From the Munson Record:618
    Abigail received from her father 12 March 1796, ‘in consideration of his love, good-will and affection’, 12 1/4 acres “in the Great Swamp” (Morris Co.). She received another favor from her father and mother (Elizabeth) 5 Sept. 1806. She was recognized as a “half-way member” of the First Church in Morristown 29 April 1784. Abraham was so recognized 2 July 1791. Administration on Abraham’s estate was granted to Wid. Abigail and to Silas Allen 30 Nov. 1797. The church dismissed Abigail 11 Feb. 1810 to some church in the State of N. Y.

Wills and Letters of Administration, 1804-l8l3 Book A on file in Surrogate's Office, County Court House, Waterloo.
    http://www.rootsweb.ancestry.com/~nyseneca/booka.htm
MUNSON I, Abigail Munson of Romulus, make my last will. I give my daughter Elizabeth Munroe the north half of the farm I now live on and at her decease I will the north two-thirds be given to my grandson Stephen Munroe and the south one-third to my grandson Stephen Herman Munson, son of Margaret Bunger. In case he should die under age and without heirs, I give the same one-third to my granddaughter, Abigail Munroe. I give my daughter, Phebe Richards, use of the south half of the farm on which I now live and at her decease to my grandsons Abraham Munson Richards and Stephen Herman Munson, and should they die under age and without heirs I give the same to my granddaughter Eliza Richards. I give my son Gilbert Allen Munson all my personal properly except wearing apparel which I give my two daughters Elizabeth Munroe and Phebe Richards. Whereas I make James Munroe full compensation for all services done for me, in case he bring any demand against my estate, I will my daughter Elizabeth's part of the farm be rented to pay for it. (Same as above for Michael Richards and Phebe's part of the farm be rented to pay for it.) I will my farm for use and benefit of my two daughters Elizabeth Munroe and Phebe Richards without their husbands having any right whatever to lease or sell the same. I appoint Stephen Allen and Isaac Whitehead executors. 21 Feb. 1818. Witnesses: Mather Marvin, Silas Allen, S. Kilman Doughty. Recorded 8 June 1818. Pp.170-174.