Today I found this little item about William and John Preston letters remaining at the Post office at Piqua, Ohio in 1816. I'll spend the rest of the night wondering what treasures might have been in those letters.
Our family descends of William Preston (1780-?1837), son of Maj. William and Elizabeth (?Clark) Preston [NHVR, Rumny TR]. William Preston (we call him Sheriff William Preston) was born at Runney, Grafton County, New Hampshire. [NHVR]
The last record I attribute to William Preston at New Hampshire is dated October 1808.  There is a record of marriage intention for John Preston and Mary Cook, published Gloucester, Massachusetts in 1811.  A brother, Collins Preston, died at Boston in 1812. 
We are still working to piece together details of how and when William and John Preston (1789-1819) made their way to Ohio. Defiance area histories report they were soldiers and/or officers in the War of 1812, but we have not found matching reference to the men. With his brother John, William is said one of the first settlers of Fort Defiance after the war of 1812.  Local (Defiance) research reports the Fort was abandoned by U.S. Troops "in the spring of 1815." 
William Preston married probably at Defiance, Ohio, 07 December 1820, Asenath Butler (1803-1888), dau. John Butler. 
William's brother John Preston married 1814, as the first of her three husbands, Sophia Ewing (1796-1867), dau. of Alexander and Charlotte (Griffith) Ewing.  Separately, the early Ewing family resided Piqua, Miami County, Ohio.
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 Frederick Chase and John King Lord, A History of Dartmouth College ... (1913); digital images, Google Books (http://books.google.com: accessed 20 Jan 2008), p 633 [seems vol. 2], "... and William and Collin Preston for $2000 to blast out and complete the lock."
 Gloucester, Massachusetts, "Vital Records of Gloucester ....., 2: 439, "John [Preston] of Rumney and Mary Cook, int. June 22, 1811"; digital images Massachusetts Vital Record Project (http://www.ma-vitalrecords.org: accessed 12 Dec 2007)
 "Died--," Collins Preston obituary, The (Boston, Massachusetts) Repertory and General Advertiser, Friday, October 9, 1812; digital image, NewsBank, GenealogyBank.com (http://www.genealogybank.com : accessed 18 November 2007), "Historical Newspapers" collection.
 Nevin O. Winter, History of Northwest Ohio, Vol. 1 (Chicago: Lewis Publishing Co., 1917), pgs. 404-414, chapter 32, Defiance County, pg. 405 for this reference.
 Louis A. Simmonis, "Fort Winchester 1812, The Greater Defiance (Ohio) Area Tourism and Visitors' Bureau ( http://www.defiancetourism.com/history.htm : accessed June 2006).
[6a] Wood County, Ohio, marriages, book 1, p. 2; "Mr. William Preston and Miss Assenith Butler," by John Perkins, J.P.; image copy from FHL film 406,699. They probably married at Defiance. See Wood County, Ohio marriages, same volume, same page, Billair-Gordon, marriage by William Preston, JP, and the dateline, "Defiance November 22nd, 1820" -15 days prior to Preston-Butler marriage. The Billair marriage also recorded 30 May 1821 at Wood County. Ohio created both Wood and Williams counties at the same time (1820), but Williams was attached to Wood for certain government functions until 1824. See Charles Elihu Slocum, History of the Maumee River Basin (Indianapolis: Bowen & Slocum), 528, "The Commissioners of Wood County organized the Township of Auglaise to include the territory of [Henry, Paulding and Williams] Counties. The court appointed March 7, 1820, John Perkins and William Preston of Defiance Justices of the Peace in and for Auglaise Township for a period of three years..."
[6b] Thomas Spooner, Records of William Spooner of Plymouth ... (1883), p. 253, entry for Asa Ruggles Thomas; digital images ...
[7a] Ohio Marriages, 1800-1958, database, FamilySearch.org (https://www.familysearch.org: 13 Dec 2010), cites FHL film 550177, p. 68 no 213.
[7b] Wallace A. Brice, History of Fort Wayne, from the Earliest Known Accounts of this Point (1868); digital images, GoogleBook Search (http://books.google.com : accessed 1 March 2008), for Col. G. W. Ewing, "The Ewings..." pages 23 -28, a biographical family sketch.
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3 Jun 2011: Updated entry in "Select references" to add more detail in support of a separate, pending blog entry.
2013: Removed GenealogyBank image.