He removed to Poughkeepsie by 16 June 1728 when the baptism of his third child was entered at Kingston Dutch Church. Poughkeepsie at that date was little more than a name. In 1723 Dutchess County had 1083 inhabitants. In 1785, when Capt. Concklin died, it had over 32,000. He appears first on the tax list of 1 July 1726. There are few early Dutchess land records. In 1742 John Concklin bought Boeckhout's share of the 1770-acre purchase, land on 2 Dec. 1772 he sold part of this land to his son-in-law, Henry Livingston. He sold his first home on the Hudson River front to Livingston in 1742. This house was demolished in 1910. [See Miss Reynold's Dutch Houses in the Hudson Valley for a description.]
John Concklin was commissioned Lieutenant on 17 Dec. 1744, and Captain, 27 Mar. 1745, of Dutchess County Militia. There are indications that his company saw active service in King George's War. A parchment in Adriance Library, Poughkeepsie, contains signatures of several county officers of this period, including that of Lieut. John Concklin. In September, 1755, Capt. Concklin led his company north "in response to an alarm" at the time of Johnson's Lake George Campaign. In 1756 he marched "to the relief" of Fort William Henry, then under successful siege by Montcalm. He was a signer of the Patriotic Articles of Association, July 1775. All of his sons served in the army in support of the Revolution.
Capt. Concklin, a founder of the Poughkeepsie Dutch Church, was elected an Elder in 1749, and a Deacon in 1763. In a church schism of the 1760s, Deacon Concklin headed the Conferentie party which held that the only authority for ordination lay in Holland, as opposed to the Coetus party which held that ministers could be ordained in America. When Dominie Henricus Schoonmaker, choice of the Coetus party and the fourth pastor, arrived in 1764, he found Deacon Concklin in control, and consequently was ordained under a tree. Deacon Concklin and Elder Peter Van Kleeck organized a bolting consistory, the story of which is told in Van Gieson's History of First Reformed Church of Poughkeepsie and Ecclesiastical Records, New York State, Vol. 6, p. 3926. The social scars of this battle marred Poughkeepsie life for many a year.
The Family Bible of Captain Concklin, printed in 1744 in Dutch, about 1930 was in possession of Elmer Conklin, Esq., Postmaster of Poughkeepsie. It contained only one vital entry, the death date of Capt. John Concklin - 15 November 1785. All other pages containing vital records had been torn out. We hope that they are still in existence and may come to light some day.
The will of Capt. John Concklin, dated 5 Aug. 1785, proved 31 Dec. 1785, opens: "I, Capt. John Concklin in good health but in advanced age," and mentions daughter Susanna; two granddaughters Johanna and Mary, daughters of deceased daughter Anna; son-in-law Thennis Tappan "who is married to my daughter Hester"; son Matthew; to son John my Dutch Bible for his birth right; orders all real estate to be sold; seven sons, John, Laurens, David, Abraham, Issac, Jacob, and Matthew Concklin; sons to provide for "my wife," she to choose with whom to live; seven sons to be executors. The sons Abraham, Isaac and Jacob qualified as executors, 14 Feb. 1786. No record of the death of the widow Annetje Concklin found. Children of John3 Concklin and Annetje Storm (in order of baptism and mention in father's will):
His will in 1785 mentions dau. Hester, wife of Teunis Tappen; Susanna; Anna and her dau. Johanna and Mary; sons: John, Lawerence, David, Abraham, Isaac, Jacob, Matthew.