1.   Johnston Family Tree [link died] by Lisa Ann Mashburn.

2.  Census Index:  U.S. Selected Counties, 1840 (Broderbund CD-316):  none found in Madison Co., AR.

1840

Johnston, William

NC

Orange Co.

Southern Division

p. 228

This may or may not be our subject; William JOHNSTON/JOHNSON is a very common name.  William's father was living in Madison Co., AR, so it's highly possible William was living with him there.  William's mother died in 1847, and her death could have precipitated many changes in the family.

3. 1850 Census (online at the Madison County ARGenWeb site):  Kings River Twp., Madison Co., AR, 398/398 :

William K. Johnson	41	blacksmith	NC
Doritha	38		TN
Alla T.	16		AR
John	14		AR
Sarah	13		AR
William	10		AR
Mary E.	7		AR
Rachel	5		AR
James	3		AR
Colombus	5/12		AR
John Johnson	72		NC

The elderly John is almost certainly William's father.  Living next door to James & Mary Ann (JOHNSTON) BASHAM — Mary Ann is William's niece.

3.  Archives of the MASHBURN-L mailing list (online at RootsWeb.com, Inc.).