There are several sources for Johnston Hearns recorded as a son of Thomas and Deborah. The first being the Historical Society, Papers and Records.
The second, the Old United Empire Loyalist List, Fredericksburgh Soldier King's Rangers p. R. Roll 1784, G. Haldimand 100 sold.
The third, Confiscations for Kingsbury, Charlotte Co., under the name Yards.

Johnston�s birth, noted as abt 1765 was found in Russ Waller's Hastings & Prince Edward Counties Loyalist Families p.180. It is believed he was born at Phillipse Patent, Dutchess County New York as his father Thomas, paid taxes there up to and until 1766. It should be mentioned that Dr. W.K. Burr, in his book Historical Sketches of Prince Edward County pages 240-241 indicates that the family origins were German from Palatinate-on-the-Rhine who came to America in 1710.

Johnston was baptized along with his siblings on February 20, 1788 at Fredericksburgh as recorded in the book Register of Baptisms for Fredericksburgh, Baptisms in 1788, page 31

He gave his age as 23 when recorded in 1782. Source/Event lists: War Office Records: Returns of Detachments and Companies of the Kings Rangers and Loyal Rangers stationed in Lower Canada. Reference: National Archives of Canada: Microfilm Reel No. B-2867 (MG 11, W.O. 28/10), p. 143. Other information indicates his birthplace as "from Dutchess"

His war record reveals little about this fourth son of Thomas and Deborah. An example of entry in Payroll Book of Capt. Henry Ruiter's Company of the KINGS RANGERS covering 1779-1782. "Balance due from you at sattlemont (settlement) & 7sch. 9 pence. By your rations commencing the 25 aug. 1781 and ending the 24 Dec. being 122 days at 2 1/2 per day is in Halifax currence(sic), to the doctor's and bakers bill for 18 weeks 3 sch." and so forth.� Clothing and drink are also mentioned. Since none of the three brothers signed their name, it is written as Harns.
Johnston was first mentioned in muster rolls taken at St. John's on 27 July 1781 (ref. War Office 28/4/96). Next list dated the 1 Jan 1782 gives Johnston (sic) as being 23 yrs of age. He is also on the final list as being qualified for Bounty lands, this having no date (War Office 28-2/10 f. 100-101). Also listed in a published muster roll, taken 21 Jan 1783 on "Rolls of the Provincial Corps., Canadian Command, American Revolutionary Period" by Mary B. Fryer, 1981, p. 101-102.
This information was supplied by Albert Smith, Adjutant, Kings Rangers, H. Ruiter's Co.
It should be mentioned here that Mr. Smith also states that the list of settlers to Fredericksburg township is in error as it places them in the K.R.R.N.Y.; as this township was given to the Kings Rangers for settlement, and not the Ruiter's Company.