Not that easy a question to answer - looks disputed.
http://homepages.rootsweb.com/~wayland/terrill/pafg28.htm#997
Mary TERRILL [Parents] was born about 1690. She married Micajah CHILES.
Other marriages:
MILLS, Matthew
There is some dispute as to whether or not Mary is a dtr. of William. An article in the Virginia Historical Magazine (volume not given) on the Chiles family, does not know her first name, but says that she was a dtr. of Joel Terrell, Sr. This is based on records (Land Book XXXVIII, pp. 524-25, dated 6 April 1769) showing that John Chiles, son of Mary and Macajah, inherited land from his grandfather Joel Terrell. "(Copy): Whereas by patent, under seal of our Colony and Dominion of Virginia, bearing date of the ninth day of July, one thousand seven hundred and twenty-four, there was granted unto Joel Terrell one tract or parcel of land containing four hundred acres, lying and being in the County of King William, now Caroline, etc.; and whereas John Chiles, in whom right and title of part thereof supposed to contain 250 acres is etc., found to contain by survey 255 acres etc., Henry Terrell enters suit on same for accounting of the extra 5 acres in order to settle lines etc. Land said to adjoin that of Manoah Chiles." Mary's two daughters married sons of William Terrill and Susannah Waters. If she were also a dtr. of William Terrill, it would mean that they both had married their own uncles.
This lends weight to the idea that she was not the daughter of William. The dates of birth are just estimates and I suppose that it is possible that Joel Sr. was one of the first children of William and that he had this Mary who was of the age that Micajah Chiles could have married her.
—-
In addition to giving her her second husband, you want to examine the parents of Micajah Chiles also.
“ Micajah CHILES [Parents] was born in 1690 in , Caroline Co., Virginia. He died in 1734 in , Caroline Co., Virginia. Micajah married Mary TERRILL.
Dicken says that the "Chiles family was among the old and prominent familes of that part of Virginia". Micajah's will was proved in Caroline County 8 Nov. 1734 by Martin Hackett and Ann Terrill (O.B. 1733-1740, p. 160)
His father is in dispute. Some say that he is the son of Henry Chiles of Hanover, VA., who may have been a descendant of Lt.Col. Walter Chiles. (Ellsberry Terrell Bulletin).
And also this
http://homepages.rootsweb.com/~wayland/terrill/pafg23.htm#464
Timothy Terrill moved to Bladen Co., N.C. about 1743 and he and John Brooks were associated. It has been further suggested that William and Susannah had another dtr. Mary, who m. Matthew Mills, as Henry Terrill and Matthew were associated in some business and Matthew had a son, William Terrill Mills. There are no authentic records of the birth of any of William's children.